M51 with C9.25 EdgeHD and cooled DSLR

[Alfredo Beltran]

Hi

 

I want to share with you this picture of the M51 Whirlpool Galaxy. For me this is special because it was the first time I used the C9.25 EdgeHD at f10 (previously I used it with the hyperstar at f2.3) and also a home made cooler for the modified Canon T1i DSLR. Mount is an iOptron iEQ45.

 

It is a composite of 33 x 5 min (2hr 45 min total) at ISO 800 with the IDAS D1 filter.

 

 

The cooler dropped the sensor temperature between 15C and 18C; without it would have been around 23C to 25C, so I got a reduction around 7C to 8C. Let's consider that thermal signal cuts in half by every 6C drop, then I estimate dark current went down to less than 50% of what I would have had without the cooler.

 

I only had to make a small crop in the borders because I use dithering. The EdgeHD really shows the definition on the borders of the image.

 

Tell me what you think about it.

 

Thanks for looking!

 

Alfredo

Bogotá, Colombia

[76doublebass]

Very interesting I may try at F10 just to see what type of results I may obtain on different DSO's. I do see where I can get a special 7.5 focal reducer from Starizona that may give me further options for imaging other than just using Hyperstar.

[Alfredo Beltran]

It is worth to try it at f10. The only risk is you don't like the image. So, give it a try!

 

Best regards

 

Alfredo

[admin]

Pretty nice Alfredo.   I really like M51 because it's the first DSO I actually imaged and processed.  It holds a special place for me.

 

Guylain

[Alfredo Beltran]

Thank you very much Guylain!

[Israel G.]

Very nice picture Alfredo... Congrats!!!!

[Alfredo Beltran]

Very nice picture Alfredo... Congrats!!!!

 

Thank you very much Israel!

[fmhill]

Great job, An excellent image of one of my favorites and what I think is a most interesting galaxy.

 

Thank you for bringing it to us.

[Alfredo Beltran]

Thank you very much, Mitch!

[76doublebass]

How were you able to auto guide at F10 with your C9.25? What auto guider are you using?

Were you able to see it in screen preview in Backyard EOS and center it as well?

I would like to know because I have a C11 and have never even tried to image M51 at my focal length and thought it would be impossible thus I never have even attempted it, but I may try since I just picked up a Lodestar auto guider. In my situation I would probably need to use my F6.3 reducer if I tried.

[Alfredo Beltran]

How were you able to auto guide at F10 with your C9.25? What auto guider are you using?

Were you able to see it in screen preview in Backyard EOS and center it as well?

I would like to know because I have a C11 and have never even tried to image M51 at my focal length and thought it would be impossible thus I never have even attempted it, but I may try since I just picked up a Lodestar auto guider. In my situation I would probably need to use my F6.3 reducer if I tried.

HiI use the C9.25 EdgeHD on an iOptron iEQ45 mount. My guiding setup is an Orion Starshoot Autoguider with a Stellarvue F60M3 finderscope/guidescope. That little finderscope came with the Finderscope rings for Scmidt Cassegrain type telescopes as you can see here: http://stellarvue.com/f60m2.html .Those rings and support don't allow for flexure because are mettalic, not plastic (my opinion, of course).I did a careful polar alignment by the CCD drift method using the DSLR. After that I ran the polar alignment routine included on the mount. When I slew to M51 it wasn't perfectly centered but was on the Field Of View. Keep in mind that a Canon DSLR at 2350 mm has a FOV of just 32.6 by 21.8 arcseconds. After having the galaxy on the FOV center it was easily done. I think that depending on your mount you can give a try at f10. That image was by far better than the one I did on my former C6 SCT at f6.3 with the same mount and camera. The light gathering capacity of the bigger telescope really helps. Notice also that I use ISO 800 but could have gone with 400 which I use with the hyperstar at f2.3.Best regardsAlfredo