Addicted to portable imaging! Feat. Horsehead Nebula

[that_guy]

In my ever growing quest to find the best (and cheapest) portable set up continues. I've been experimenting with AZ GTe mount in EQ mode with the new firmware and guiding. I've found that with this mount, you should only guide in RA as DEC has too much backlash to be usable. This is a huge step up from the star adventurer which is a completely manual mount. Having the option of GOTO and platesolving as well as wireless control through wifi is a game changer. AND it's the same price as the star adventurer (give or take $50 depending on where you source it from). There's no reason why you wouldnt take this over the SA.

On to the image itself, I would have preferred more subs but weather wasn't allowing it. I've been using the club's QHY8L which I'm beginning to see the limitation of (a lot of star bleeding and limited resolution and cooling being the prime factor). I got a lot of the feint bits that I'd like to add Ha to with my QHY9 but that would decrease FOV. I think I have too high of an expectation for this set up.

ED72
AZ GTe
QHY8L
38 subs @ 120 seconds

Astrobin link (https://www.astrobin.com/383689/0/?real=&nc=ToeKnee419) for all you pixel peepers

[Peter Ward]

The colours in your image are pretty good, but with alt-az tracking you are getting field rotation that will only get worse with more subs....hence you might want to consider an Eq head, assuming you want to go deeper and improve image resolution.

[RyanJones]

Great image Tony.

120sec on the Az-gte is impressive. Well done.
I've only just stepped over to an EQ. Like you, I wanted portability so I stayed with my Alt-az for a long time.

Peter, the Az in in EQ mode. You don't get field rotation, if you did, 120 sec wouldnt be impossible.

Great work Tony !

[Peter Ward]

So you can put one of these puppies on an EQ wedge? Cool.

(But if they just track by moving in altitude and azimuth then simple geometry means you will get rotation)

[that_guy]

skywatcher released an unofficial firmware update that tracks in RA DEC instead of Alt Az. Pretty nifty. Still a few kinks and bugs but I'm looking forward to more stable updates!

[Peter Ward]

OK, excuse me if I am teaching you how to suck eggs here....but it matters not what co-ordinate system is used to track an object.

If the head is not polar aligned and on a wedge, then it is making simultaneous adjustments on both axes to follow an object across the sky.

So, if you were to take a picture of Orion early in the evening, Rigel would be above Orion's belt. But as Orion is setting it will have done a 180, and Rigel
will be below the belt...hence simply tracking the object will show this rotation.

An Alt-Az set-up can however be made to de-rotate the field by using a camera de-rotator... Meade instruments had one
(https://www.meade.com/meade-1220-field-de-rotator.html) but they were discontinued a while ago.

[that_guy]

This is what the setup looks like. The camera is the only thing thats different.

[Peter Ward]

OK, so polar aligned on a wedge :thumbsup:

[RyanJones]

I was fairly sure from looking at the mount that it worked exactly the same as my alt-az on a wedge. Basically the RA axis is polar aligned then through tracking it only rotates on the RA axis. That was the geometry I had in my head.

What I'm impressed with is 120secs of smooth enough rotation from such a small head and light weight tripod with that setup on it. I had gym weights and everything on mine to smooth out the vibrations. The big advantage you have over mine is the counterweight.

I'm really impressed Tony :thumbsup:

[multiweb]

Nice HH. Very vibrant colours. :thumbsup:

[ChrisV]

Sweet portable setup Tony

[RickS]

Nice rich colours, Tony. Well done!