Thursday, April 30, 2009

Tele Vue Ranger transformed

The focusers side by side, they're with similar length. The JMI has much shorter travel due to the lack of that sliding draw tube, the fine focusing range is not differ by much. However, you can remove that extension tube (1.5" long) for more in-travel for the NGF-S.

This is the custom made adapter, with perhaps 1-2mm more female thread, it will look better. Anyway, it works.

Focuser attached, very elegant and the Ranger has a new life. Shall I call it a Pro-ger?

Last night, I tried to put my 2" mirror diagonal there, and as expected, with the extension tube of the NGF-S, it couldn't reach focus, I've to slide the diagonal a little bit outside. With the extension tube in place, it could not too. Anyway, it's my design since I wanted to retain the most in-travel. By keeping the diagonal a little bit out from completely flushed in, it's secure enough. All of my eyepieces and barlows work in this way, slide out a little bit and that's it. Maybe a 2" filter thread extension tube would serve as a more elegant draw tube for quick focusing, but it's all later work.

The transformed OTA is shorter than before, and a little bit more heavy as expected. The focuser could be easily removed and re-orientated. That would enable it to sneak into my Fast Pack 350 without problem. Excellent portability.

Tomorrow if the weather allows, I shall try to use it on the sun with my Solarmax 40/BF10, that's going to replace my Borg 45ED II and I shall also try it out with a 0.5x binoviewer corrector.


So before the sunshine comes, I try to put everything together and point it to terrestial target to test the focus travel:-

Attaching a small EQ mount on the window frame?

I have always been thinking how to put my mount closer to the window, the closer my mount to the window, the more field of view that I got get. A pier should be perfect, but such a small pier might need tailor making and it would become very expensive.

Today, I saw a few screw holes on the window frame, so I wonder if I could attach a small EQ mount there? Let say my Takahashi TG-SP II, it's small but it's powerful enough even to hold my C5, and yesterday night, I actually tried to put that Orion 100ED OTA there and it works. Frankly, the C5 is like 6lb and the Orion is like 7lb only but it's longer, so it's not too surprising to see that it works.

Therefore, I shall see if I can find suitable mounting hardware when I got more time. At the first glance, it should be feasible.

20090430 Sun

Cloudy, cloud cover is over 70%, but I dare to try. Seeing 3/10, transparency 0-3/10. Borg 45ED II, Solarmax 40 with BF10, DMK 31AF03, Meade LXD55.

1454 (GMT+8), I did the prominence first since there's always cloud around and by pushing the exposure up, no more cloud could be "seen":-

1455 (GMT+8), this is taken when I found the cloud around was not so thick:-

Finally, a closeup at 1505 (GMT+8), with 2x barlows, AR1016:-

Wednesday, April 29, 2009

Tentative to-sell list

I want to trim down to absolute minimum, so I'm drafting this list:

1. C5 with DIY focusing motor and control box with USB charging port, SCT reducer

2. PST hacker's version: with etalon adapter, 6.5" ERF, 52mm ERF

3. Gitzo G1415 with LXD55 adapter, LXD55 head, counter weight

4. Borg 45ED II with 2" visual back and NGF-S adapter

5. FCUSB, 1.25" EOS adapter, Meade 1.25" prism, 9mm meade adjustable reticle, and other small adapters

6. Binoviewer with 0.5x and 2.5x corrector, two matched 20mm Tele Vue Plossls

Please contact me if you're interested to any of the above, I'm not in a rush to sell all these, but in the long run, I hope to minimize.


So I'm keeping my Ranger for solar imaging and portable observing. I'm keep the Unistar Lighter as the visual observation mount, I'm keeping the TG-SP II for deep sky imaging and solar imaging. I'm keeping the Orion 100ED for white light imaging with my Herschel wedge, as well as deep sky visual observation. I will keep all the eyepieces as well.

Orion 100ED first light

It's not exactly the first light, but it's definitely the first light in the conventional sense. The first light received was on the sun via H-alpha filter set, and white light in Herschel wedge. This time, it's under the night sky! Sad to say it's under my urban home sky only.

Transparency is low like 3/10, and there is only under 5 naked eye stars. I pulled out my Gitzo G106 (!!!) with my Unistar Light to mount this long OTA! Given the light weight of this OTA, this mount handles it well at least at the low power which I've tested. I only tested with my 40mm Pentax SMC XL.

I've to lock the focuser a little bit more than usual with a 2" mirror diagonal and that Pentax, otherwise it will slip slowly downward. Therefore, I guess I ain't going to cut the OTA for binoviewer unless I plan to change the focuser as well.

The view through the eyepiece is superb! At f/9, the Pentax performs extremely well and the field is very flat indeed. No need to re-focus for even the stars close to the field stop. Stars are absolutely pinpoint, the contrast is very high. If you ever view through an SCT, you will know refractor stars are far finer! And I don't recall seeing so many stars in a "random field of view" from inside my home. On quick scanning, you see no star, but once you stop, the stars pop into view!

I can't wait to bring it to darker sky!

Tuesday, April 28, 2009

20090428 Sun

Telescope: Borg 45ED II
Filter: Coronado Solarmax 40 with BF10
Mount: Meade LXD55
Camera: DMK 31AF03

Seeing: 2/10
Transparency: 3/10

1349 (GMT+8), this one is taken with Tmax closed:-

1350 (GMT+8), this one is taken with Tmax tuned by my usual style, this method brings out the prominences most at the expense of non-even illumination:-

1351 (GMT+8), push up exposure to bring out all prominences:-

1423 (GMT+8), this one is taking with a PST without etalon (don't do this with your eyes!), but there's nothing shown apparently:-

Monday, April 27, 2009

Existing solar equipments

The PST OTA was left idle after removing the etalon module. Today, I tried and concluded that the PST etalon module is pretty parfocal, what I mean is that, on adding it and removing it, the amount of focus travel is negligible (within 5mm), therefore, the PST should be able to reach focus without it. Of course, it's not going to work for solar observation since the etalon is missing, but how about if I put a Solarmax 40 in the front?

I can't think of any reason why it won't work, the bandwidth should be tighter too! Therefore, I guess if I ever sell my Solarmax 40 and BF10, I can bundle the PST as a part of a value added package while I keep the PST etalon for other purpose. Seems like a Maxscope 40 on the cheap.

I should take some solar shots with this setup!

20090427 Sun

Telescope: Borg 45ED II
Filter: Coronado Solarmax 40 with BF10, also PST etalon module
Mount: Meade LXD55
Camera: DMK 31AF03

Seeing: 4/10
Transparency: 2/10

First two shots were taken without the PST etalon module. The first one is taken at 1410 (GMT+8):-

Notice that the prominence shot has the internal reflection issue (upper right area) reduced, since I have sticked a (under-sized) black sticker to cover that shinny central obstruction inside the Solarmax, so I guess if I managed to find a black sticker which matches the size of the central obstruction, the internal reflection will be gone, 1411 (GMT+8):-

But I know I ain't going to use an oversized sticker since it will reduce the valuable clear aperture. Okay, finally, the last shot taken with PST etalon module, 1414 (GMT+8):-

The same shot but processed by Registx v5:-

Optical path length of my diagonals

Just did some quick measurements:

Generic 2" mirror diagonal ~ 11cm
Tele Vue 1.25" mirror diagonal ~ 8.2cm

Since the BF10 is measured to be around 7.3cm, so my previous approximation is too rough really.


Ranger Transformation Project on the lauching pad:

1. Measured once again for the focus position:

- With 2" mirror diagonal and 2" Pentax SMC XL 40mm, I will need to pull the diagonal at 0.5cm outside to reach focus, which is good enough... given the adapter might have some length (sure it will), the focus travel is about right.

- With the 2" mirror diagonal and my 1.25" 20mm Widescan Type III, it's around "parfocal" with the Pentax 40mm when used with the 2"->1.25" adapter

- With the 2" mirror diagonal, the 13mm Nagler requires more out travel, so maybe I will need to use my filter thread extension tube on the Nagler, so it's also use-able

- 5x Powermate is parfocal, so there's no problem with that Nagler!

For solar imaging, since the BF10 has around 4cm optical path less than the 2" mirror diagonal, my 1.5 inch 2" extension tube from the JMI NGF-S will work perfectly to make that up! Everything ready!

Measuring the optical path length of Coronado BF10

It's hard to see anything other than the sun visually with the BF10 in place, however, it's dangerous to see the sun without the BF10. That makes it hard to measure its optical path length. Before the test today, I just use a mirror diagonal as a very rought approximation.

This morning, I attempted to use my DMK to do this job. Don't get me wrong, I will not use unfiltered sun for measurement. Instead, I use far away terrestial target with long exposure.

With the BF10, I set the exposure long enough to show the object on screen, guess what, with maximum gain, the exposure requirement would be like 1/4s. Without BF10, I use normal day time exposure.

So, the measured optical path length is around 7.3cm.

Saturday, April 25, 2009

Tele Vue Ranger has a new life!

The lens is removed from the cell, and rear assembly is taken off, and I will pass the tube to a local folk for making that NGF-S adapter. After making this adapter, the NGF-S could be rotated to any angle, the NGF-S could be removed quickly so that the OTA is short enough to sneak in my Fast Pack 350, so the whole thing will become extremely portable.

The 2" capability means the lowest magnifications would be 12x giving more than 5.4 degrees true field of view! That's going to be wonderful. Feels like a lighter and smaller Pronto.

On the other hand, the motorized focusing ability is going to make it a perfect telescope for solar imaging with my Solarmax 40 and BF10. I believe that it's going to replace my Borg 45ED II. The Borg is a very nice scope, but then it's too small for most other purpose except for guiding or snapshots. However, since my longest lens is just a 200mm, no guiding would be required. I would sell my Borg 45ED II afterward, most probably. For full disc solar imaging, I would go back to mosaic, or a simple drift with my renewed Ranger.

The Ranger is always lovely to me, despite it has been sitting idle for quite long, I really wanted to use it again since I always have a special relationship with it. It carries lots of memory as my first real actively used telescope. I can't wait to use it under the sunny sky, or the starry sky!

Best of all, this project is always reversible, since there's no intrusive modification.

Friday, April 24, 2009

Ranger to NGF-S adapter

The ulgy drawing, and the thread on the Ranger side is a kind of uncertain:-

And here is the Mini-Borg to NGF-S adapter, so this one is just to replace that M57P0.75 with the thread to the Ranger:-

Thread Specifications of the Ranger side:-

Thursday, April 23, 2009

Ranger rear assembly thread size

I have a hard time to confirm the specifications of the thread. Originally, I tend to think it's M77 since the objective lens cell has M77, but now I believe that it's not:

First of all, I think it's more like 3 inch rather than 76mm or 77mm:-

The hardest part is the thread pitch, if the diameter is 3", the thread pitch should also be in inch?

And here is how it looks when measured against centimeter:

This is how it looks like when unthreaded, basically, all you need to do it to slide the dovetail outward and you can see a screw directly under the dovetail, loosen it and you can unthread the rear assembly very easily.


Two more shots:

Wrinkle on front filter

As we all know, wrinkles on Baader solar film will not affect image quality. However, why is that? Is it because the film is so thin?

If that's the case, I'm wondering if I can use simple red plastic sheet as ERF?

Don't do that with your eyes, however.


Experiment: I shall put a thin piece of transparent plastic (e.g. those food wrap) in front of a refractor and try it out at high power, but this should not be done on the sun in any case.

Ranger Transformation Project Re-open

Today, I found another secret screw on my Ranger, now I could remove the whole back assembly including the dovetail, the draw tube and the focuser. The thread is M77 (or M76? or 3inch? pending confirmation) male and now I have a few more centimeters!

I placed my NGF-S there, and I can reach focus with my 2" mirror diagonal + Pentax SMC XL 40mm, I can reach focus with my 1.25" accessories... I just need a little bit more out-travel but then it's easy... I can make a slightly longer adapter to connect the NGF-S and it's done.

The adapter should look very much like this one:-

which I have made for my Borg 45ED II before. Of course, it's not M57 to connect to the OTA, but it's another specification: 12mm of M77 female thread.

So, if this project is implemented (i.e. make the above adapter), my Ranger will be able to take 2" eyepiece (new life indeed!), as well as motorized focusing which is especially useful for solar imaging with my Solarmax 40, that means I can sell my Borg 45ED II afterward.

Of course, the Borg is great for full disc imaging due to its shorter focal length, so I've tried to use a SCT reducer, but there is not enough back focus. I might want to try out a 0.5x binoviewer corrector to see if it works or not. If it works, there is no reason that I should hold this project.

I always want to find some use with my Ranger, and if that could be done, it's just perfect!

Wednesday, April 22, 2009

Summary: Cutting Orion 100ED

(1) I can cut 3" (or 7.6cm) and I can still reach focus with all my existing barlows and eyepiece combinations without using any extension tube

(2) I can cut 2cm more if I forget about using my 3x barlows.

(3) My binoviewer has an optical path length of ~12cm, so if I were to use it without any corrector, I will have to cut ~12cm or a little bit less due to the fact that the focuser is not racked all the way inside for the eyepiece with most in-travel.

(4) I have two extension tubes on hand, one is 1.5" and the other one is nearly 3" long, but I would want to use only one of them and I prefer that 1.5" since shorter means better.

Therefore, I can cut 4.5"... that translates to 11.43cm and it's just a little bit less than the required 12cm. Real life situation always ends up like this. LOL

Optical Path Length Measurement

It's cloudy, so what to do? Previously, I've sent an email to Sibert Optics to ask for the optical path length of my Black Night, however, I didn't get any response, and I guess my email was probably trapped by the spam filter. So, why not measure it myself?

I pulled out my Borg 45ED II:-

I found that I can reach focus without a diagonal... so, it's time to remove the binoviewer and to use the eyepiece alone:-

I found that I've to use two extension tubes with a total length of 11cm and I also have to extend the drawtube on my Borg by around 1cm more. Therefore, the optical path length of the Black Night binoviewer should be around 12cm...

So, if I want to use the binoviewer without corrector with my Orion 100ED, I should then cut it by around 12cm.

After this experiment, I pulled out my Canon 10x30 IS for a quick comparison. The binoviewer Borg yields around 16x (with two 20mm Tele Vue Plossls). The view from the Canon is much brighter, and the 3-dimensional feeling is also stronger. Anyway, there is really not much a reason to use a binoviewer with a 45mm scope.


Harry replied and it's 12cm officially.

Monday, April 20, 2009

Reaching farther out for the sun

Summer is a bad season for solar imaging from inside my home... Previously, I used a long platform plate to let my scope mounted farther outside, I even used a binocular L-bracket to push it one or two inches more outside... those were poor solutions indeed.

I just tried to shuffle the stuff a little bit, this time, I placed the platform plate between the tripod and my mount, so it looked like this:-

To do this, I've to reverse the Gitzo to LXD55 adapter upside down, to put a 3/4" screw from the bottom of the adapter to fix on a threaded hole on the platform plate. The LXD55 mount head is then fixed via a slot on the platform plate. This setup is very secure and stable, since the other side of the platform plate is indeed resting on the window frame. However, I have no way to adjust the polar alignment since that tripod stub is missing here. I should free up the Gitzo to LXD55 adapter in order to get back this function. To replace that adapter, I need to use another aluminium bar with a long enough 3/4" screw to fix it on the tripod. That will not look as elegant but it will work.

The original 3/4" plate of the Gitzo has too short a screw, since that platform plate is quick thick by itself.

20090420 Sun

Equipment failure! It's one of the most terrible thing that you can see when you see your target is there, but you cannot do anything!

I pulled out my notebook immediately... After all the connection, things were ready. My notebook is too slow that I can only get around 10 fps instead of the usual 30 fps with my desktop. Anyway, it's better than no imaging.

Seeing 3/10, transparency 2/10, taken with my Borg 45ED II, Solarmax 40 with BF10, DMK 31AF03.AS with Meade LXD55. Featureless basically.

1549 (GMT+8):-

Later, I found that my PC has its 1394 getting loose... I removed the plug and put it back, no use... and then I shaked the plug inside its socket, it works... This is the setup which I used:

My notebook has only one 4-pin 1394 port which does not deliver power (vs. 6-pin), so I have to hook a 12V SLA to the 1394 hubs to give the power to the camera.

BTW, this shot is processed with Registax 5.

Friday, April 17, 2009

20090417 Sun

First and the most important of all, a new active region is coming....

Okay, seeing 3/10, transparency 5/10. First two were captured with my Borg 45ED II, 52mm ERF (i.e. 45mm effective aperture), PST etalon module plus BF10, no internal reflection for this setup, but then illumination is still uneven:

1652 (GMT+8):-

1653 (GMT+8):-

Then I replaced that ERF with my SM40, so the effective aperture is now 40mm like before... the narrower bandwidth really brought out that new active region at the limb, taken at 1658 (GMT+8):-

Wednesday, April 15, 2009

An updated family photograph

Orion 100ED f/9, Borg 45ED II, Tele Vue Ranger, and my C5 with DIY focusing motor, and that PST at the back. The tallest brother is really too tall.

Tuesday, April 14, 2009

More information on the Orion 100ED

The objective cell thread matches that of the Tmax of a Solarmax 90! I am not and will not be able to buy a Solarmax 90 for it, but this is a good starting point to verify the thread size of the cell. :-)

I have fine tuned the focuser according to the instruction here:

Now, it's just smoother and I suppose that it should hold more weight as well.

Next, I found that common binoviewer would take up around 4 inches of optical path, so if I cut the OTA by 4 inches, I would probably be able to use binoviewer without any corrector. The focuser travel of the Orion 100ED is more than 5 inches, so it could probably make up the differences. And in the worst case, a very moderate extension tube like 2-3 inches would make it work again for normal operation.

Such a shortened tube should be able to let me focus with a focal reducer, as well as to make it more portable. Not a bad move indeed.


Follow up on the thread size, thank Edd Weninger from CN:-

Hi Oldfield,

I just measured the threads on the SM90 T-Max at:

4.25" Outside Diameter
24 Threads per inch

This is not listed as a standard thread size in my Machinery's Handbook so I have no clear tolerances for it.

Noting that it appears to thread into the E100 seems unusual (my ED80 has Metric threads), so it might be possible the thread pitch is 1 mm. There is not much thread length to work with for the thread gauge.

However, the Outside Diameter would then be 108 mm, which would seem odd for a Metric dimension.

I'd suggest that if you are having something custom made, that you provide the mating part to the machinist.

Edd Weninger


I have checked with all my eyepieces. Assuming that I will be using a 2" mirror diagonal, I could safely cut the OTA by 8.5cm without the need to use of any extension tube to reach focus for all my eyepieces and barlows combinations. To leave some safety margin, cutting 3 inch would be very safe.

Given I have a JMI 2" extension tube which is 1.5 inch in length, cutting 4.5" from that OTA would be no problem. People said binoviewer took around 4-5", so it might work as well.

20090414 Sun

The sky is foggy, but the sun can penetrate the cloud somehow. Transparency 0.5/10, seeing 3/10... Borg 45ED II, Solarmax 40 with BF10, The Imaging Source DMK 31AF03.AS, Meade LXD55 mount:-

1612 (GMT+8):-

1613 (GMT+8):-

Saturday, April 11, 2009

You gonna love white light!

Okay, let's go through H-alpha first. I took two images as usual with my Borg 45ED II, Solarmax 40 with BF10:-

1334 (GMT+8):-

1335 (GMT+8):-

And after this usual image at solar minimum, I did a very strange experiment. Guess what, I replaced the Solarmax 40 with a ERF, and guess what, prominences still come out! That means the BF10 is indeed powerful and narrow enough for prominences! I didn't use my eye, I just used my camera. Take no risk, right?

1338 (GMT+8), less prominences could be shown despite to the wider bandpass:-

Then, I pulled out my Orion 100ED for some white light game with my Herschel wedge. One of the reasons that I bought this OTA is for white light imaging, I dreamed that solar maximum is coming and white light imaging will become interesting again... So, I did an experiment first. It wouldn't quite reach focus with the stocked 1.25" adapter, but I replaced it with a real low profile one and I got around 0.5cm to spare. Not bad. The view is impressive!!! No sunspot, but you could see some hint of detail across the disk!

1356 (GMT+8):-

Binoviewer couldn't reach focus, the Herschel wedge sucks up too much in-travel, and that 2.5x SCT corrector couldn't help in this case, despite it used to work with all my refractors. No, it works... I should have placed the corrector in the nosepiece of the Herschel wedge (hot!) rather than the nosepiece of the binoviewer. The view is nice! Now, I really want sunspots!

Friday, April 10, 2009

Your Life Long Scope

People always said that we have different telescopes for different reasons, let me list the most common types:

1. Your grab-and-go scope, which is usually a small refractor which requires little cool down and setup time

2. Your light bucket, which is usually a dobsonian or maybe a SCT, that would be the biggest scope that you could afford both financially and in terms of portability

3. Your astrograph, which is usually a fast refractor, a fast telephoto prime lens, or something similar

Today, I think of another important type of scope, it's your life long partner.

Believe it or not, if you're spending more than ten years of time in amateur astronomy, you're going to buy and sell telescopes during the process. Good telescope is not what you need, maybe just like your wife, she's not going to be the best girl in the world, but she's definitely the one who's the most suitable for you. Telescope could be similar, you won't need the biggest or the best one, but you need one which you can use most, suitable for your purpose, budget, portability, etc. The only exception maybe that you could always own more than one telescope but you could only have a single wife. (Of course, your single wife could prohibit you to own more than one telescope, too)

Okay, let's go back to the topic.

A life long telescope is one which you:

1. will never sell for some reason

2. can use it no matter where you go, and no matter how you change your observation habbit/style

For me, this is definitely my Tele Vue Ranger. Yes, it's not a very good telescope in terms of the standard today. Any small Chinese APO refractor which is both cheaper and more portable could out perform it. However, for reason (1) above, this will be my life long scope. Why? This is my first telescope which I really actively used (my physically first telescope is a Celestron C90, but that one rarely get used enough), and I spent so many hours in the night sky (and day sky) with it, and I've so many good memories with it (together with my lovely wife). And it probably has a very low resale value now, and that means that the motivation for me to sell it should be surprising low, but the reasons to keep it is exceedingly strong.

Secondly, this scope fits criteria number (2) very well, too. For some reasons that I know I'm going to sell my Orion 100ED, my C5, my Borg 45ED II, and I had sold my C8, my half Sky90, my C90... I know all of them will need to go one day, since I will not be able to keep them and use them enough. But my Ranger, will continue to serve me and I can take it along with me to whatever places.

Which one is your life long partner?

Thursday, April 09, 2009

20090409 Sun (poor seeing)

The seeing was extremely bad. Transparency was low too. I checked my filters and scope thinking that there's something wrong with that.

1426 (GMT+8), nearly no feature:-

1427 (GMT+8), very poor:-

I waited for an hour, finally got slightly better seeing (still very poor) at 1532 (GMT+8), but then we have some much thin cloud moving around:-

Wednesday, April 08, 2009

Another DIY Project

Summer is coming, and the sun is going to a bad location from inside my home window, solar imaging is getting harder to do. Last year, I use a long platform plate to mount the scope closer to the window so that it can reach farther outsider to catch the sunshine. But it's quite problematic due to the imbalance, and it's also hard to me to push my head out to center the target.

I already want a table top tripod, but it's either hard to buy or it's too expensive (Vixen SXW mount has such a thing) just for a single purpose. A table top tripod is more compact so that you can push it closer to the window, as it's shorter so that sunshine will be always available.

So, how about making one myself? Making a tripod could be hard... So, how about a short pier? I have a LXD55 tripod hub around unused and that could be use for mounting the LXD55 mount head to it, and under this hub, I need something like a pier to set the whole thing on.

I want something which is tall enough to clear the counter weight shaft, but it should be as short as possible otherwise. This tripod should be stable enough for a C5 OTA as well, it should be able to handle the imbalance due north from a GEM.

I have some ideas in mind, time to search for suitable materials.

The Ultimate "Star" Test

By ultimate star test, I mean that I'm using the Star - our Sun. :-)

The sky was no good today, but it's doable. First up is my Borg 45ED II, and the sky condition was the worst by then. Next is my Orion 100ED with cheapy-ERF, PST etalon, 2.5x binoviewer corrector and a BF10... Finally is my C5 with the new DIY motorized focusing, cheapy-ERF, PST etalon, and a BF10.

Borg 45ED II:-

Such a long OTA of the Orion 100ED is proven unuseable indoor, even when I've tried all sorts of angles and combinations, part of the aperture were still blocked and the room for slewing is essentially zero. Anyway, I took a few AVIs with it despite the aperture is at least 40-50% blocked.

Orion 100ED with PST etalon and BF10:-

However, the C5 works perfectly with some rooms to slew around.

C5 with PST etalon and BF10:-

I can already conclude that the C5 is the best thing for indoor purpose, if I were to stick with a GEM for tracking, altazmount could be another story.