Cat Paw Ha

[multiweb]

Here's another attempt at the cat paw. All I could fit in last night with the C11/hyperstar between the clouds and the moon. About 10x5min + 15x10min. In retrospect the 10min subs might have worked better without the moon nearby :P.

I got caught (again) with a bit of field rotation in the top right corner because I didn't pick a guide star close enough to the center of the frame but overall I got more details than the 3h or so I did with my newt. It kind of clouded over early, nearly packed up, but then it cleared after 11:00pm. So I shot as much as I could until it went down but the moon was very bright West. Oh well, will have to try again. I'll get it right eventually. :)

[gregbradley]

Hmm dunno Marc. Focus looks a tad off and perhaps some deconvolution or unsharp mask on the whole image that makes the stars a bit harshed out. Your earlier images with the same rig were much better.

Greg.

[multiweb]

True - Collimation issue I think. I'm trying to get the rig to work at prime focus and it seems that I can't have both hyperstar and prime working together on the same alignment. Too cold to tweak things outside right now. :)

[David Fitz-Henr]

A nice image Marc - pity about the elongated stars in the top right. Are you sure it's field rotation? It would be intersting to see some test shots each side of focus. If it is tilt, you will see the star shapes change through focus (sagital / tangential elongation).

[multiweb]

Thanks David. Yeah bit of both. The whole field is tilted but I have field rotation already in half of the subs. Getting there with collimation and what not. I have learnt so much about SCTs in the past 3 weeks that I have been playing with the Hotech kit. But it has been very time consuming and quite frustrating at times :P. The design for the primary attachement is the last hurdle. Now I have everything else tight and quite easily adjustable it's the only thing I have no clear control over. Might be more suited as a summer job. Too cold now. If I could find a way to image a small artificial field of stars that would be great then I could do this on the bench like the rest of it. Would a laptop picture at a distance work? I'm talking only about field flatness and tilt, not diffraction rings as in start testing?

[CoolhandJo]

But still a great fov and detailed shot!

[Bolts_Tweed]

Great capture mate

The dynamic range is covered really well as discussed in the other thread. Damn theres some faint Ha in the region isnt there?

Yeah the collimation and rotation can annoy but a quick band aid could fix it - the main part I think (the extent of the Ha and detail in it) is fantastic.

Aaaaah - can you hear my lust for aperture

Mark Bolton

[strongmanmike]

That framing looooks veeery familiar ;)

Actually it is interesting that we have the same FOV... but I need to use a dinner plate sized sensor to get it all in :lol:

Nice job Marc :thumbsup:

Mike

[jase]

Marc, I have to agree with Greg. I think you've also over done the sharpening. Stars appear a little too crunchy and punctuated against the background. Very good extension to the nebulosity however. Perhaps ease up on the sharpening and evaluate the data set with fresh eyes. Deconvolution may not be the best option.

[multiweb]

Thanks Paul :thumbsup: too kind.

Thanks Mark. No doubt the hyperstar is a light bucket.


Thanks Mike. Yeah I saw your shot on your site. Terrific work.



Agreed. I could have presented it a alot better. I was more concerned with the field. I didn't deconv but I did try to remove sky noise due to moon glow and that probably did it along with JPEG artefacts. There's a clearer version here (http://tinyurl.com/2f7f6y4) although still affected by sky glow but less compressed.

[Hagar]

Nice image Marc. Looks like you have been following me and sharpen,sharpen, sharpen. I get a bit carried away when I find something that works.

[Tom Davis]

Very nice depth and detail. I always think this objects looks best in H-alpha and presented in B&W.

Tom

[gregbradley]

Right. Collimation is something I am going to have to get used to again soon.

The revised version looks nicer.

Greg.

[TheDecepticon]

Another nice one Marc!:thumbsup: Gotta love the Hyperstar.:)

[multiweb]

Thanks Doug. Yeah looks like it but I haven't. With moon glow it was too noisy to deconvolve or sharpen to start with. I think the JPEG compression in the small version buggered the dynamic range and the stars.


Thank you Tom. I've seen some real nice Ha shots of the area on the web. Definitely a lot of neb around.


That's the thing. It's the same file but saved differently. I shouldn't have posted the small compressed version. I bit the bullet and I'm making a small obs in my backyard. SWMBO suggested 'a shed' so I jumped on the opportunity and will start pouring concrete soon. It's now or never. I'm sick of hauling the whole scope and mount back and forth. With all the collimating and testing of late it's running me down. I need something fixed to work efficiently and align this whole rig properly. Then I'll be good to move around off site.



Thanks Grey. Yeah it's great to use.

[Bassnut]

The artifacts on the small post overwhelm the detail IMO ;), makes it hard to evaluate.

[danielsun]

Nice one Marc, a little rotation on the right there but still incredible detail!!:thumbsup:

Cheers Daniel.

[multiweb]

Thanks guys. There's a bigger version here (http://tinyurl.com/2d9wlbq)but still not that good. True, the reduced version is ridden with JPEG artefacts. The shot is actually a square crop of a much larger field, about twice as big but it wasn't centered at all so I cropped around as the rest was pretty boring The original is here (http://www.astropic.net/astro/NGC6334_HS3_ha_f.jpg) if anyone wants to have a peek [800KB file].

[gregbradley]

That's the thing. It's the same file but saved differently. I shouldn't have posted the small compressed version. I bit the bullet and I'm making a small obs in my backyard. SWMBO suggested 'a shed' so I jumped on the opportunity and will start pouring concrete soon. It's now or never. I'm sick of hauling the whole scope and mount back and forth. With all the collimating and testing of late it's running me down. I need something fixed to work efficiently and align this whole rig properly. Then I'll be good to move around off site.


That's the way to go. One observatory I built was a simple modified garden shed and it worked very well. I simply reinforced the frame with pine timber. I then built a frame for the roof to roll off behind it.
Then I made some trusses for the roof to strengthen it and make it more rigid to handle the roll off. Then simply put some wheels on some timber that the bottom of the roof sheets were screwed to.

I put a few latch type locks to hold the roof down when closed. It rolled off very smoothly and easily which was important as my neighbour then was fairly close and I didn't want to make a lot of noise at 1am or 2am closing the roof so it had to be smooth and quiet.

I then added some flashing to the wall and roof as the roof was now higher than it was originally. Worked very well and was large enough for one setup and a computer table.

If you want more detail PM me. I have virtually finished my new observatory which is larger and more detailed.

Not so sure pouring a concrete floor is the way to go. I just dug a large pier, filled it with reinforcing steel and then road base around it, paving road base then pavers. I left a small gap between the pavers and any pier or pad. That way no vibration transmits to the pier and ultimately the scope. Also thermal differences are minimised. 50mm thick pavers cool quicker than 100mm or more of concrete.

Greg.

[multiweb]

Thanks Greg - PMd.