20130701 Cheung Chau, using a Canon 100-400mm f4.5-5.6L as a telescope

Visual observation basically,except I helped some of my friends to take images of the Milky-way area with the help of a tripod.

This is a camping event with the youngsters from the church.  This time I brought my Canon 100-400mm and used it as both a camera lens and telescope!  If we treat it as a telescope, it's just very compact and extremely portable, and it allows zoom. 

In order to use it with a diagonal, I've added a Tele Vue 2x barlows in front of the diagonal so as to give enough focus travel.  Given its 4x zoom range, it's versatile enough with just a single 20mm Widescan Type III.  Actually, I also had a 4mm TMB planetary with me, but I was too lazy to pull it out.  Before I went for this observation, I tried these combinations at home at terrestrial objects to make sure infinity focus is alright with certain image clarity.

Conventional estimation gives 3x in such a configurations of barlows and diagonal, so I have 15x with a real field like 5 degrees and it is huge!  Searching for target is rather easy, but I didn't bring any finder or zero power sight devices, so I need some scanning which is not exactly enjoyable with my 410 head.  Maybe due to the complex lens configurations, the view is rather dim at its widest.  Also, notice that the Canon 100-400mm has f4.5 effective focal ratio at 100mm, therefore, the effective aperture is just 22mm!  So technically speaking, it is a stronger reason why it was so dim.


Stars were basically pinpoint across most of the huge 80 degrees field, open clusters were well resolved but again, it's dim.  Pushing up the magnification does not give dimmer image  since it has more than 70mm effective aperture at 400mm.  Swinging it to Saturn reveals it's oval shape even at 15x, by pushing up to 400mm, we have 60x which has its ring resolved very nicely!

Conclusion: given its small effective aperture at 100mm, it is not really a wide field instrument but its wide field capability could make it serve as a finder of its own.

20130618 Moon with Canon 100-400mm f5.6L with 5x powermate

Good transparent at 7/10, seeing 2/10, moving cloud.

Focus was off, since the computer screen was rather far away from my lens so I cannot adjust really accurately.

The shadow like double image was a result of such focusing inaccuracy, will do it again soon!

I'm dreaming...

I didn't come back for several months because I never had my hands on my telescope for some time.  Night time traveling could be quite difficult right now and day time observation is very limited, too.

Now, I wanted to buy a H-alpha solar filter for myself again.  Any good suggestions?

I've a single requirement: cheap, I don't need something powerful.

I don't mind 2nd hand, DIY, hacking or whatever.

20130128 Sun

1457 (GMT+8), taken with Ranger at prime focus.

2013-01-21 Sun

Again prime focus and 5x:

1547 (GMT+8):-

1549 (GMT+8):-

2013-01-14 Jupiter

Didn't do planet for very long, especially now I only got a 70mm refractor.  But I asked myself, my hobby started with this 70mm refractor anyway, and that's also why I'm addicted, so here we go!

Armed with my Mark-X, I walked down stair to a nearby playground where I have some more skies.  Inside home for this particular season, I couldn't have Jupiter in a good viewing angle.  That's why I have to go out.  Now, I only got a Lu070M so I couldn't do color easily without a filter wheel, so why not just go monochrome?

So here is my setup, my trusty Tele Vue Ranger with its original focuser, with a 5x Tele Vue Powermate.  Tracking done with my GOTO Mark-X using a self hacked Tele Vue System mount motor.

My Asus Eee PC has its hard drive broken a few months ago and after replacement, I haven't run K3CCD on it yet so the initial setup wasted me like 10 minutes or so.  Cloud rolled in and I nearly missed the capturing chance!

I've viewed through it with my Widescan Type III 20mm which yields 120x, and I guess I should have brought my 4mm TMB with me!  Anyway, the disc is big enough for me, the purple fringing is okay, not too annoying.

Taken at 2331 (GMT+8, the left one), and 2333 (GMT+8, the right one), not bad indeed... I enjoy!

2013-01-14 Sun

Again at prime focus and 5x Powermate respectively:-

1637 (GMT+8):-

 1641 (GMT+8):-

2013-01-09 Sun

No time to process until today, first shot is at prime focus and the second one is with a 5x Powermate.

1550 (GMT+8):-

1555 (GMT+8):-

2013-01-02 Sun

Continuing my solar imaging, first up is at prime focus, 1557 (GMT+8):-

Next two were taken with 5x Powermate, 1605 (GMT+8):

1607 (GMT+8):-

Finally, I pulled out my new acquired TMB Planetary II 4mm to have a look, very nice and contrasty, easy to view through with a wide apparent field of view!  The eye cup is very nicely designed (not good looking, however, a bit thin) for shielding out light easy at day time, eye relief is plenty. 

2013-01-01 New Year Sun

My Ranger has gone back to its original shape, the NGF-CM was sold earlier last year.  Solar imaging has been going back to basic in white light with Baader film, and cheap green 1.25" filter from China.

The first one was taken at 1454 (GMT+8) at prime focus:-

And the next one was taken with a 2x barlows, 1457 (GMT+8):-

These shots were taken with my Mark-X using a hacked Tele Vue System mount motor driven by a solar battery.  It's nice to harvest solar energy to do solar imaging:

 Lastly, happy new year!

TMB Planetary II

Ordered three TMB Planetary II eyepiece with relatively long eye-relief, adjustable eye-cup and also wider than standard field of view, the quality is very nice!

Actually, what I really want is the 4mm to be used with my Ranger for planets and moon.  The 7mm and the 9mm will be up for sales very soon, expect good pricing like $50 USD shipped.

New in box.

2012-10-24 Sun

I've sold my NGF-CM recently and also my only 2" eyepiece, so I am falling back to 1.25" built-in focuser of my Ranger, doing manual focusing as well.

taken at prime focus, using ebay CaK filter together with Baader 3.8.  This filter is sold soon after this shot was taken.

Using a Lumenera with a camera lens

I have an adapter on hand and why not give it a trial?

 

 So, here is the result:

So a camera lens can do pretty good, and it may even serves as a telescope in that case.

2012-09-03 Sun

20120903, 1411 (GMT+8), ebay CaK filter, Baader 3.8, Lumenera Lu070M, Ranger at prime focus.

\

20120714 Sun

Lumenera Lu070M, ebay CaK filter used, Ranger with original focuser, mounted on Gitzo G106 with Manfrotto 410 head, no tracking.

Prime focus (1519 GMT+8):-

With 2x barlows, (1521 GMT+8):-

A new small adapter: camera lens as telescope

It allows us to connect an eyepiece, or a CCD camera to a camera lens.

For the eyepiece end, it features a nice thumb-screw with compression ring.

And for the camera side, it has a standard Canon EF/EF-S mount. 

I've tested it straight through with an eyepiece, and it reaches infinity focus without problem.  If a star diagonal is used, one must insert an 2x Barlows in front of the diagonal.

When used with my Canon 200mm f2.8L, it works as a rich field scope in the straight through configuration.  With a diagonal is inserted together with a 2x Barlows, it works as a nice medium power 70mm refractor.

I can offer these small adapters at $49 USD each airmail shipped.

Cabinet clearing sales

Package deal: $500 HKD takes them all! 


Individual items price reduced, all reasonable offer will be entertained, just don't want to waste all these stuff.

Canon EOS to 1.25" nosepiece adapter, bought from ScopeStuff, ask for $180 HKD, connect your Canon DSLR with a telescope with 1.25" focuser.


SkyAtlas 2000.0 Deluxe Version, ask for $180:-

And the inside, a pen is placed along side to see the size, it's really a good visual reference!

Next is a 70mm doublet (f=500mm) mounted and with 77mm thread, suitable for macro imaging which brings the closest focusing distance down to less than 500mm. Ask for $100 HKD.

Celestron Nexstar mount parts, the gears were still available at $80 HKD as shown below, the bigger one was about 6" in diameter and the smaller one was 5".  Someone said they have "24 pitch teeth".  The bigger one has 288 teeth and the smaller one has 240 teeth. The central bore is 22mm. (SOLD)

Another custom machined 2" to 1.25" adapter, it's pretty heavy and could be good for balancing light weight 1.25" eyepiece and heavier 2" eyepiece. With two locking screws for added security.  Ask for $50 HKD.

Originally for my Gitzo G1415 when I lost one of the spikes on the legs, so I still have two remain. I've sold my G1415 and now they're sitting idle... very hard to find in Hong Kong and even the distributor refused to order them for me. Ask for $100 HKD.

在浩瀚宇宙中尋安身之所

站在小小的幾方呎裡，遠望廣闊的大地，發現可安身的地方實在不多...

站在廣闊的大地上，遠眺眼前的海洋，感到可安身的地方實在亦不多...

站在無邊的海洋前，遙看浩瀚的星空，驚覺可安身的地方實在也不多...

站在天際之間，回望深不見底的心靈深處，才明白安身之處根本闊不過一條窄路。

(寫於大嶼山塘福海邊觀星後)

2012/06/06 Venus Transit

Equipments:

1. Canon 450D + Canon 100-400mm f4.5-5.6L, (Kenko 2x sometimes used) with Baader 3.8
2. Lumenera Lu070M + Tele Vue Ranger + Thousand Oaks Type 2+
3. Gitzo G160 + GOTO Mark-X with DIY motor and mounting accessories

Location: Nam Cheong Playground (南昌公園)

First up is one of those earlier shots, taken with the Ranger setup, the focus is less than perfect since I found that I've to push up the brightness of the display in order to show clearly under strong sunshine despite I was already using an umbrella.  Battery life was greatly reduced in that case, so I'd rather save the energy for 3rd and 4th contact.

2. So we did a fast forward and now it's close to 3rd contact, I've fine tuned the focus this time.

3. This is just a hair before 3rd contact and there is no obvious black drop effect.  I would say black drop effect is not a must and it's probably a combination of suboptimal optics, atmospheric issue (seeing), less than perfect focus, etc.  Even with only 70mm of aperture, the thin line between the planet disc and the solar disc was resolved nicely.

4. This is the 3rd contact.

5. The moment passed 3rd contact, notice that the atmosphere of planet Venus was shown protruding outside the solar disc, I've pushed up the exposure to make it clearer.

6. Venus was getting out further, the atmosphere arc was shown better.

7. The moment just before the 4th contact, I have to add an arrow in order to see the last trace of transit.

8. This is the 4th contact, but it's virtually the same as if there is no more transit, since this is the moment when the planet disc was completely out of the surface of the solar disc.

Second set was taken with my Canon 450D setup, and it's less than perfect as expected.  I should have used the Thousand Oaks filter with this setup in order to optimize the Ranger setup, but I was not smart enough to do so.

1. This is the earliest one, even earlier than the Ranger setup since I can do it handheld without much setup. 

2. Cloud kept rolling in briefly and away, and it's not too bad to have cloud around especially when it's just oh-so-hot!

3. For most of the time it was boring so I've skipped those moments and let's go to where it's closer to 3rd contact.

4. Black drop effect is about to appear...

5. The infamous black drop effect!  I believe it's not the quality of the optics for this particular case, but stacking actually help to eliminate the effect of atmospheric seeing!  That's why those images taken with the Ranger setup is sharper.  Day time seeing is even more unstable.

6. Planet disc was getting away...

7. The moment just before 4th contact.

Finally, I include a few snapshots so as to remind me of the hot moments under the strong sunshine.

There are over 30 passerby who observed and chatted with me on topics like simple planet knowledge, solar physics, cosmology, politics, education system, eschatology, camera, old days of Hong Kong, etc.  Around 5 people spent more than half an hour with me, and 10 of them came back periodically to check up the moment of Venus!

World without strangers for astronomy!

The ballhead side of the Mark-X is not easy to use for 400mm shots, so I will have to re-center it periodically and it's not a good exercise, so I pull it off and use it handheld with a Kenko 2x, since I'm using Baader 3.8 and the sunshine is strong enough even at f/11 with ISO 100, at faster than 1/2000s shutter, handheld is never an issue.

For those who are careful enough, you will see now I've a bigger umbrella and a piece of paper on the floor.  Those were given by those passerby to me!  

 My legs were darkened afterward and it's a nice morning indeed.