Monday, May 29, 2017

20170529 Short imaging session


Quite windy these days, so I brought only the Ranger for this fun imaging session.


The moon is setting, so this is just a prime focus shot, taken at 1222 UT.


And we have a 2x shot, of the Jupiter, taken at 1228 UT.


Finally, push up to 5x, i.e. 2400mm focal length, taken at 1236 UT.

Using the Ranger is much easier for this Nexstar mount.

Thursday, May 18, 2017

Further testing of the Canon FD 300mm f2.8L in scope mode

I have done some work on the internal reflection issue before, but no testing since then.  Today I have a cloudy afternoon and thus it is a good chance to test it out with a EOS 1.25"adapter.

First test was conducted with a diagonal. Yes, it won't focus unless I add a barlow in front of the diagonal or a 2x extender, 2x extender seems more elegant.  In short, it's sharp with my 20mm eyepiece.  I expect around 50x with this configuration.

Pulling the diagonal off should be a better test, it's even sharper since the effective focal length could go down to 300mm!  I took the plunge to use it at 3000mm, yes, 3000mm by using a 2x extender plus a 5x Powermate, and so we have 150x and it remains very sharp and contrasty, too.

I guess I should try it out with the moon or the planets, probably with a camera.  I hope it could replace my C5 eventually, if it is also good as a 4" refractor.

 --

After writing the above short report, I pulled it out again to try higher.

First test was with 2x extender with a TMB 4mm, so we have 150x again.  Sharp and no image break down.

And then I added a 2x barlows in the same setup, so we have 300x!  Floaters come in but again no image break down, focusing was easy.

I'm quite confident now.


Thursday, April 27, 2017

20170418 Jupiter

The sky has been cleared for a few days, and I finally cannot hold myself but to have some simple imaging time.

I placed the Nexstar mount plus accessories into a small backpack and hand holding my C5, heading to a nearby small playground.


I just set the scope up like this, to save the effort about dragging the tripod out.


The Nexstar mount has quite some backlash and the backlash compensation was not fine tuned enough, keeping the Jupiter in the field is not easy...


The collimation must be very bad.


Here is the result after processing;


And this is the prime focus shot, those with a barlows were too bad to show.

Thursday, April 13, 2017

Minor revamp of the Canon FD 300mm f2.8L

I removed the ugly hot melt glue and replaced it with eproxy putty.  I might paint it back later.

I tried to compare the focusing chip which utilizes the phrase detector, with the live view and the result is consistently effective and accurate.






And then I set it up on the Sky Adventurer, and it supports well, and the counter weight is far more than enough.  Both the internal RA motor slews well, and my DIY DEC motor works well, too.





You can also see the Polemaster above.

Really want to try it out under than stars.  I have several prime lenses,  a 8mm fisheye lens, a 50mm f1.8, a 200mm f2.8 plus this 300mm f2.8, and that should be enough for quite many targets.

Thursday, March 23, 2017

A smaller focuser controller

I have a dead 18650 charger, so I removed all the circuit board inside, solder two small switches on the top to make a small focuser controller for my JMI.


It's powered by a 18650 inside, I could even add a small rheostat inside to adjust the speed.


When I don't need to DRO control unit, for example, like for a more compact setup like visual trip, this small controller could be used.

Wednesday, February 01, 2017

20170201 Sun

Cloud keeps moving around today, seeing 5/10, transparency 4/10.

Don't really have time to fine tune to focus or the T-max.


0706 (UT), with reducer:


0710 (UT), with 2x barlows:-


0711 (UT), with 2x barlows, that interesting filaments attracted my eyes:-


The last image really shows how poor is the T-max, very uneven bandwidth across this little frame.

Friday, January 27, 2017

Polemaster and Sharpcap 2.9+

I went last night without any luck, the sky was too bad.

Tonight the sky seems a bit better, so I went again.  A nearby light polluted sky, with the polar region partially blocked.

Since I've tested with Polemaster software, and tonight I play with Sharpcap 2.9+.  If the automatic plate solving works, it's simpler for the Polemaster software requires manual pattern matching.

To my surprise, it works out very nicely!

Here's the screen shots of how it works... Plate solving success...


And then rotate along RA, success again... 


After polar alignment with Sharpcap, I proceed with the software of Polemaster and it works!   Confirmed the alignment.


And then I removed the polarscope caps, saw Polaris in the expected position!  I hope I could do some wide field imaging soon!