Dark skies / short FL

[aparker]

Heading up to my place in dark (-er than Boston) New Hampshire this weekend, I was bemoaning the fact that there was going to be a great cloudless, dry night Saturday, but the 3/4 moon made it kind of pointless to get the Dob out to hunt for faint fuzzies.  Then I got the idea to grab the Ultrastar and make use of a telescope that I've owned for years but rarely get out.  So, I set up my AT72 (ED doublet, f/6 for ~430mm FL) on the Celestron AVX mount I bought as a portable EQ solution.  After looking at the moon visually for a while, I decided to see if I could get a decent photo of it with the Ultrastar.  I knew it would be way too bright for even the shortest possible exposure, so I threw on my 6nm H-alpha filter to cut the incoming light, and set SLL to 0.02 sec (the shortest it will go).  This is what I got (unstacked, obviously, just a single shot).

I suppose if I was really into this I could get one of these USB3.0 ASI cameras that is meant for this and get even shorter subs.  And figure out one of these planetary stacking programs...or not.  But it's definitely recognizable, if not as crisp as it looked through the eyepiece.

Leaving the H-alpha filter in place, I wandered over to M42 and ran off a bunch of 10 sec subs.

This is obviously an incredibly difficult object because the difference in brightness is so extreme from Trapezium to extended nebula.  But I was pretty happy with the view for 5 minutes total.  Especially for a 3" scope.

I took off the H-alpha filter and went over to Bode's "nebulae".  Bumped the exposure to 30 sec to try and pull in more of M82.

M81 is pretty blown out in this one, which I stretched as much as I could to bring out more in the outer parts of M82.  Still pretty cool for a 3" scope with a 3/4 moon out and no attempt to filter.  The LP in Boston would definitely be a bigger problem that the moon here in NH.

Continuing the bright galaxies in UMa theme...

I kind of like the context that the wide field provides, although this is a bit too short for M51, IMO.  You can just see edge-on IC4263 at the bottom of the image.  Finally, M101.

 Stretched super-aggressively to try and pull out the fainter spiral arms, so it's a bit grainy.  You can see NGC5477 near the top.

Overall this worked rather better than I was expecting, and has me motivated to haul my c8 and CGEM up here the next clear moonless night I get.  I'm very interested to see what really dark moonless skies will do with my usual EAA setup.  I'm also even more tempted by this experience to take the Hyperstar plunge, as it would (on the C8) yield about the same FOV as the AT72 has, but with 7 times the light grasp.

 

[aparker]

Astrometry.net says these images are 71 x 54 arcmin at 3.08 arcsec/pixel, BTW.  A pretty nice place to be for sensitivity, and not too bad for resolution given the usually lousy seeing we have around here.

[Astrojedi]

Alex,

Great shots. Another one I would have tried with the At72 and HA filter is the Rosette.

I use my AT72ED with my iOptron Cube pro mount as a travel setup and it is quite enjoyable. Although it will never rival the light gathering capability of larger scopes it definitely provides very enjoyable views especially on large nebulae. 

Hiten

[laudropb]

Nice set of images.

[todd8137]

Great work for you and that scope of your 

pat

[aparker]

8 hours ago, Astrojedi said:

Alex,

Great shots. Another one I would have tried with the At72 and HA filter is the Rosette.

IHiten

That would have been a good thought, if I had thought of it...  I worked on M42 until it was pretty close to the trees, but could have gone after the Rosette after that.  Looking at it in Sky Safari, it would really require even a shorter FL than the AT72 to get all of it in the FOV of the Ultrastar.

[aparker]

Here's a testimonial to how good the live stacking and image adjustment in SLL actually is.  Saved all the 10 sec subframes from the M42 run above, and this morning spent about an hour fooling with them in Nebulosity.  The final result I came up with is marginally, and only marginally, better than what could be done live with SLL v2.1.  Pretty amazing, IMO.

[aparker]

Link to attempt at post-processing M42...

 

 

 

[RobertI]

Nice set of results Alex. I had heard that the using a narrow band filter can create very crisp images of the moon, although I realise you were using it to reduce the brightness in this case. That little 72mm scope is picking up a nice amount of detail in M42 and as you say a very pleasant alternative scale for galaxies. I imagine it was so easy to use too, I've really enjoyed my sessions with my smaller scopes. 

Like you I have experimented with post processing images I have captured during a session with SLL and have not really achieved any improvement, although sharpening has occasionally improved some objects. 

Rob

[Martin Meredith]

Great shots Alex. Amazing to see you're capturing some of the outer nebulosity of M51 (what I like to think of as the triple 'horns' on NGC 5195) even with the moon about. It would be interesting to see how much additional stuff can be picked up without the moon from the same site. 

Martin