M42 with Sigma50-500 on Star Adventurer

[neilcreek (Australia)]

I've been doing short-exposure, wide-field DSLR astrophotography for years but I've yearned for greater reach and longer exposures to capture nebulas and other DSOs. Several months ago I bought a Sky Watcher Star Adventurer tracking platform and started shooting decent shots up to 135mm with my Canon 5D3. I initially tried some shots with my Sigma 50-500mm telephoto with poor results - every shot showed random camera shake.

Last weekend I was away from the city and in a "what the heck" moment, decided to give it another try. To my astonishment, I was able to get some decent results! I set up a 32 shot, 1hr sequence of M42 and though I had to toss more than half of the photos due to camera shake, I had enough to process in Pixinsight (with dark and bias frames, but no flats) and got this result which blew me away!

You can see the photo in higher quality here: https://neilcreek.smugmug.com/Folio/...py/i-5smbNHM/A

I plan to do more shots like this, but it's really convinced me that this is the kind of shot I want to do in the future, so I'm researching a proper astrophotography setup.

15x2min
f6.3 ISO1600
500mm

[blink138 (Pat)]

that is fab neil!
my brother and i have just started on this "adventure" ourselves, we think the mount is amazing for the money and takes not even ten minutes before your up and shooting!
pat

[neilcreek (Australia)]

Thank you!

I struggle a bit with the polar alignment, partly because I'm not properly familiar with that part of the sky yet, and partly because the fine alignment is tricky: fiddly azimuth adjustments, difficult angle to look through the scope, poor eye relief with my glasses on. But once it's aligned well it can do amazing things for its size and cost

[raymo]

Beautiful, just needs the blown out core quietened down, then it will be a main forum image.
raymo

[Atmos (Colin)]

Looking pretty good there! Flats may help a lot in bringing out some of the fainter details, they can have more of an impact than you realise. If you can get them next time, I would definitely suggest that you do.

[neilcreek (Australia)]

Thank you raymo! I intend to do that the next time I image M42. I've yet to experiment with exposure blending in Pixinsight, as that's really what's required to get a shot of M42 without clipping.

Atmos, I wasn't able to lock down my focus before I had to disassemble the rig for transport, but I'll be sure to do so the next time I shoot with the 50-500. Thank you!

[dimithri86 (Dimithri)]

I showed this picture to my friend who has the same lens, and he wants to put it on my G11. And try to replicate your incrediable results.

At 500mm, how much did you have to crop the picture?

Thanks for showing us whats possible!

[ZeroID (Brent)]

Very impressive indeed, well done.

The camera shake, Is it coming from the mirror action ? If so can you add a delay in the sequence to allow the mirror to come up and settle down before the exposure starts ? DLRs normally have a 2 or 10 sec delay option in the menu. I use one of my DSLRs on the mount sometimes while it is doing other imaging to get some wide feild pix and do this to stop any vibes getting hrough.

[LightningNZ (Cam)]

I meant to comment on this sooner. It's very good! There is a bit of an overly blue cast to everything though. Just check your grey levels. There are some stars in this field that are white, yellow or red and I think you're muting them a bit. Still very, very good.

[neilcreek (Australia)]

Thank you all for the compliments!

dimithri86 I've attached an unprocessed, uncropped original sub (which I downsized to comply with the IIS attachment file size limit) so you can see what I was starting with. I've probably cropped about 50% of the image.

ZeroID I suspect the shake came from the wind. It was a little breezy beside Lake Glenmaggie, and even though the tripod was low, the 50-500 is quite long when zoomed out, so it catches the breeze and the leverage on the small mount likely was the culprit.

I shot the sequence using Magic Lantern and it's bulb timer and intervalometer. I set up the intervalometer to have a 5 second pause between shots to allow vibrations to dampen. The shake was quite inconsistent between shots as well, so I don't think it was caused by something as consistent as mirror slap.

LightningNZ thank you! Yes I agree looking at it now. Colour is a tricky thing for me, and I haven't been using Pixinsight for long, so I'm still learning and always second-guessing the colour balance. I'm sure I'll get better with more practice.

[JDStellar]

That's a pretty decent stack, I'm actually looking to purchase a Star Adventurer myself quite soon, though i've been worried about weight capacity (though if you're shooting on a 50-500mm I think I will be fine)
What is it like? Are you happy with it?

[kaizersoje (Jerry)]

Hi Neil,
I am impressed with the shot you got with the mount. What are your thoughts on it?

[VS6000 (Tim)]

That's really good from that mount! What's your alignment method?