M33.. through the astrograph

[UlteriorModem]

The 8 inch astrograph can prove some decent data as long as you crop the hell out of it!

M33-3 by Tom Whit, on Flickr

[messier 111]

nice work , thx .

[bobharmony]

Well done, Tom!

Bob

[SkyHiker]

I would call that a success, nice image!

[BABOafrica]

A little cropping here and there never hurt anybody!

Nice capture. Shows a lot of bright features.

BABO

[Greenman]

Nice work, and without being told I was unaware of the cropping. It is more annoying for you than the viewer I’m sure to leave pixels on the cutting room floor.

[UlteriorModem]

Thanks guys, yea the cropping is alot more painfull for me than the end viewer. After all I wanted that wide field of the fast newt.

But having to cut that field by 50% or so just grinds my gears and is counter productive it seems to me. If I get a chance today I will process and post the full frame for comparison.

[Astrovetteman]

WOW Tom, beautiful image! I know what you mean about cropping but for some objects it just has to be done!
Great Image!!
Tom

[MariusD69]

Awesome! Well done, Tom!

[UlteriorModem]

Here is the full frame. Did not spend alot of time processing this. There is a good deal of vigenetting and I had no flats to calibrate with. This is just for scale comparison.

M33 Full frame by Tom Whit, on Flickr

Click the image a few times and inspect the corners in the zoomed image... Sigh...

[Hankmeister3]

Nice!

[SkyHiker]

That's quite good, the coma is gone, and the vignetting can be fixed by flats. Usually you want to focus on the center anyway. There are some slightly stretched stars in the bottom corners so maybe that's a bit of miscollimation? I would not give up, as you announced in your other thread, just as you seem have got things working.

[jrkirkham]

Good job

[UlteriorModem]

That's quite good, the coma is gone, and the vignetting can be fixed by flats. Usually you want to focus on the center anyway. There are some slightly stretched stars in the bottom corners so maybe that's a bit of miscollimation? I would not give up, as you announced in your other thread, just as you seem have got things working.

It's tilt. That's just it, just when I was closing in on it it all went to crap again last night while working on the tilt. Corrected the tilt some and the coma seemed to come back.

Spent three good hours last night putzing around and making no progress, then of course clouds moved in. The field curvature is still there too. That curvature will make mosaics extremely difficult.

No as Gabby pointed out the APO is almost the same field of view with a whole lot less issues. By the time I crop the artifacts out of the images from the astrograph the APO would actually have a wider field of vies.

I just wanted to try the astrograph through the winter. Did not make it At least I have a good fall back and there will be very little change software wise, pixel scale etc.

[helicon]

Looks great Tom. Nice detailed capture.

[kt4hx]

Very nice Tom. You captured all the main features within the galaxy (as shown at the below link), to include the brightest globular, C39. Well done.

https://www.astronomy-mall.com/Adventur ... egions.jpg

[UlteriorModem]

Thanks all,

Based on all of your nice comments I have decided to get the astrograph one more try.

I was getting frustrated last night trying to adjust the tilt and the clouds kept giving me errounous info in the CCD inspector app.

I adjusted the tilt spacing to be hopefully close to zero with some feeler gauges as a starting point. Hopefully things will go better tonight.

[TheButcher]

Verry Nice Tom!

[Star Dad]

I am lost. What do you mean by "tilt"? Is this something I should be checking for. Never saw that term used before.

[UlteriorModem]

I am lost. What do you mean by "tilt"? Is this something I should be checking for. Never saw that term used before.

Let me start by saying ... no you probably do not need to worry about it. It is just that my set up with a very fast scope and extremely picky coma corrector exaggerates it.

But basically means that the imaging plane (the chip) is not perpendicular to the optical plane. It is tilted to some degree.

It's a very painstaking and often aggravating thing to chase down and correct.

I spent about an hour and a half last night trying to get it corrected, finally gave up and racked the tilt ring all the way down to 'factory defaults' and it was way better than any adjustments I had made. Did not help that the CCD inspector software was being pissy.

This is about the best article I have seen on the subject.

https://aiastro.wordpress.com/2019/01/2 ... djustment/