Whale Galaxy

[Xiga]

Hope everyone's keeping safe in these uncertain times. 

Hard to believe it's been just over a year since i last posted something using new data. Where did that year go?! As luck would have it, a few weeks back, i collected all my astro gear from the old family home, where i do used to do all my imaging and moved it down to our place, where the skies are worse, and the sky views are much more obstructed. I wanted to have another go at using the C8 for imaging a galaxy, and luckily there was a clear night last week, so once the kids were asleep i set about trying my luck on the Whale Galaxy, as i knew it would definitely clear the tall trees at the back of the house. 

After spending far too long faffing about with an OAG and an old IDS-UI camera (which i now know isn't up to the job) i finally gave up on the OAG idea, but rather than just pack up, i decided to throw the finder-guider on there anyway and just see how things went. Time was against me, i only had a 2 hour window left, so could only dither every 3 frames. But at least the guiding held up well (under the circumstances) with the HEQ5-Pro. It went down as low as 0.67" at one point, never went over 1", and seemed to average at around 0.85", which was way better than i was expecting. 

I don't have an actual SCT FR, so to continue the bonkers theme i actually used my SW x0.85 one lol. Solving a frame in Astrometry gives an actual FL of 2,320mm (total insanity, i know) or F11.4 😂. 

I'm also just glad to have now finally got to use the Qhy163c that i bought off another SGL user in Spring of last year. So it only took me a year to get an image out of it! 

So this is:

40 x 180s (Gain 80, Offset 35), -15C

C8, HEQ5-Pro

Stacked in APP, and processed in PS. SGP was reporting HFR's from about 5.1-5.8. I've no idea if that's ok or terrible at this FL. I was just surprised that all 40 subs were keepers tbh, with none having trailed stars. 

It's a noisy beast i know, so apologies. And that's even with a generous dollop of NR and downsampling to 35% of the original size. It needs a tonne more exposure. Something i could have addressed the following night, which was also clear, but alas, i was way too tired to even consider it. But it was fun just to be out imaging again, even if it was just for this. I might even try it again, if the weather plays along that is!

CS folks. 

Edited March 24, 2020 by Xiga

[tooth_dr]

Looks good Ciaran, nice to see you imaging again.

Lots of colour and detail, the OSC is a success!  The background has suffered a little from the lack of dithering, but this is only a minor comment!

 

Keep them coming please.

Adam

[JamesF]

I had a little peek at this myself last night, but didn't do any imaging other than to test it for how well it filled the frame.

I wonder if the FR is actually of any value at all?

James

[Xiga]

2 hours ago, tooth_dr said:

Looks good Ciaran, nice to see you imaging again.

Lots of colour and detail, the OSC is a success!  The background has suffered a little from the lack of dithering, but this is only a minor comment!

 

Keep them coming please.

Adam

Thanks Adam. It was nice to actually image something again. If I'd managed to get the 5 hours I was hoping for, and not just 2, I might have had something half decent, rather than the disappointment that was this. It actually needs downsampled even more than this tbh. Best viewed no closer than 10 feet from the screen! 😅

[Xiga]

2 hours ago, JamesF said:

I had a little peek at this myself last night, but didn't do any imaging other than to test it for how well it filled the frame.

I wonder if the FR is actually of any value at all?

James

The standard F6.3 SCT FR will give a wider Fov, which would matter for larger targets. But it won't get you any more photons on a target that already fits, and it also produces terrible stars in all 4 corners. 

Tbh the C8 is not an imaging scope at all. This was simply a case of me having a go with what I currently have. I've never even considered picking up the SCT FR as I know it would be a disappointment from an imaging standpoint. I think it's more of a visual accessory rather than an imaging one.

Edited March 24, 2020 by Xiga

[JamesF]

Seems odd though that you ended up with a measured focal length greater than the native focal length.  I wonder if the FR is physically long enough that it increases the focal length by more than it decreases it optically?  Perhaps not helped by the OAG if you left that in the imaging train.

James

[JamesF]

Hmm.  I'm not sure I've explained that very well.  I know what I meant, but it's hard to write

James

[Xiga]

I understood perfectly James 😃

It's simply down to the extended optical train. My C8 has a Crayford focuser (which also increases the FL). After that it goes: Hotech SCA T-adapter - Baader Clicklock. Then the SW FF/FR followed by 55mm of spacers. This way, focusing and rotation are both easy, and the optical train is totally solid. No thumbscrews in use!

When I finished I didn't touch the optical train, I just carried it up to the loft. Here's a pic:

Pretty bonkers looking I admit though 😂

Edited March 24, 2020 by Xiga

[JamesF]

Just now, Xiga said:

Pretty bonkers looking I admit though 😂

You're not wrong there

James

[Xiga]

Thought i'd give this one last go at processing, because, well, what else is there to do on these cloudy nights holed up at home?! Plus, i just can't get enough of crummy data it would seem, lol. 

Colours were all wrong, plus it was seriously lacking in contrast. Dialled the stretch back a bit, and have also downsampled it further, it's down to 25% now, which i believe brings the effective pixel scale up to about 1.36" now. Well, it is if you ignore the fact it was taken on a C8 that's never even been collimated once in 7 years 😂 Also added quite a bit more NR (okay, a LOT more NR), but with only 2 hrs of >F11 data there was simply no other solution. 

So yeah, not one for the purists, to put it mildly. This one was just for fun. A crazy image for these crazy times we are living in.

CS.