Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_30_second_exp_2_winners.thumb.jpg.b5430b40547c40d344fd4493776ab99f.jpg

Uranium235

Rosette under a full Moon: Smash & Grab

Recommended Posts

As the title suggests, this wasnt done under ideal conditions - but given the run of awful weather and only a few hours of clear sky until the next storm - I decided to set up in order to get as much clean data as possible, it the shortest time possible... so I binned everything!

I think ive got this newtonian lark sussed out now, no need to replace the focuser as Ive luckily stumbled upon a very good position for the secondary mirror on the 130PDS (which I will never touch again!). Which became evident once the first sub rolled off, good stars in all corners and loads of signal coming through - not surprising since the 130pds at 0.89x, binned 2x2 is 4.6x faster than unbinned on the 80ED. Shame the sampling rate is a slightly dodgy 4" p/p. But given the weather, I would take anything!

I havent quite been able to eradicate the gradient caused by the full moon, but its as much as I can expect given the conditions - which ranged from ok, to bloomin awful - which is when my FWHM values shot up and everything went a bit Mr Blobby. Hence a trip down the garden to see if my focus was off,  nope... dew? nope. Must have been a patch of high cloud or mist... who knows?!

Caldwell 49: Rosette Nebula (Ha)

14x450 + 1x 1200 (for luck) 

130pds (0.89x), Atik 383L+, NEQ6

Calib: Bias and Flats

Setpoint: -20

Minimal cropping

Thanks for looking! :)

Rob

post-5513-0-27940700-1392408198.jpg

post-5513-0-27940700-1392408198_thumb.jp

  • Like 5

Share this post


Link to post
Share on other sites

Cheers :) Im quite relieved that the little 130 has started to deliver on demand, all it needs now is a run under a moonless (and properly clear) sky. Shame the current state of the weather forbids imaging over multipe nights (since you never know when  youre going to get out again!), so its hard to really get stuck into anything properly. 

Share this post


Link to post
Share on other sites

I think the 130pds is proving to be a little gem of a scope Rob, Especially when paired with your atik383. Thats a really good image of the rosette in very poor conditions and binned 2x2. So all looks well for the future. Good idea to leave the secondary well alone! :smiley:

Share this post


Link to post
Share on other sites

I think the 130pds is proving to be a little gem of a scope Rob, Especially when paired with your atik383. Thats a really good image of the rosette in very poor conditions and binned 2x2. So all looks well for the future. Good idea to leave the secondary well alone! :smiley:

Thanks :)

Ive come to the conclusion that you dont need to get so hung-up on getting the secondary exactly centred under the drawtube. As long as is still reasonably centred under the focuser after you have made adjustments to centre the primary spot under the cheshire crosshairs, then it should be ok for imaging on sub APS size sensors. The most important thing is to avoid rotation, easier said than done when its a tube I can barely fit my hand into - so trying to hold the secondary still while making adjustments its a little tricky!

I might do a reprocess later, it still looks a little fuzzy - and can probably afford another little curve or two.

Share this post


Link to post
Share on other sites

In the insane world of AP this is a budget setup but, boy, if this is what you can do under trying circumstances then bring it on! What a great result.

I suggest to our beginner guests that the spend needs to prioritize in the order Mount, Camera, Optics and what better confirmation could we have? A mount that is one up on the minimum, a first class CCD camera and a set of modest but perfectly competent optics. What would you have gained with a Takahashi?  Honestly, not a lot.

Great to see someone out at night in the UK as well! Curse those jetstreams with no sense of direction...

Olly

Share this post


Link to post
Share on other sites

Ive had a little tinker with the data again to see if I can kill off that gradient a bit more, and stacked it using SD mask rather than sigma clip (it didnt kill off all the hot pixels in the original):

post-5513-0-72795600-1392456496.jpg

post-5513-0-72795600-1392456496_thumb.jp

  • Like 2

Share this post


Link to post
Share on other sites

It's a super image Rob, and all credit to you as well for investing the time (and skill) to fully optimize your kit - the results speak for themselves. 

Martin

Share this post


Link to post
Share on other sites

In the insane world of AP this is a budget setup but, boy, if this is what you can do under trying circumstances then bring it on! What a great result.

I suggest to our beginner guests that the spend needs to prioritize in the order Mount, Camera, Optics and what better confirmation could we have? A mount that is one up on the minimum, a first class CCD camera and a set of modest but perfectly competent optics. What would you have gained with a Takahashi?  Honestly, not a lot.

Great to see someone out at night in the UK as well! Curse those jetstreams with no sense of direction...

Olly

 A HEQ5 Pro is more than enough for this setup and still makes it very portable to dark sites.

Share this post


Link to post
Share on other sites

 A HEQ5 Pro is more than enough for this setup and still makes it very portable to dark sites.

I don't disagree.

Olly

  • Like 1

Share this post


Link to post
Share on other sites
ollypenrice, on 15 Feb 2014 - 09:28 AM, said:ollypenrice, on 15 Feb 2014 - 09:28 AM, said:

In the insane world of AP this is a budget setup but, boy, if this is what you can do under trying circumstances then bring it on! What a great result.

I suggest to our beginner guests that the spend needs to prioritize in the order Mount, Camera, Optics and what better confirmation could we have? A mount that is one up on the minimum, a first class CCD camera and a set of modest but perfectly competent optics. What would you have gained with a Takahashi?  Honestly, not a lot.

Great to see someone out at night in the UK as well! Curse those jetstreams with no sense of direction...

Olly

Thanks Olly, its been a bit of a learning curve to get this far with that little scope but ive been determined to make it fit for CCD imaging. Perhaps the only thing missing now is 2" filters to kill off the vignetting in the far corners. But I may have to find a cheaper way to do it, which would be to use my existing 1.25" filters in a 2" wheel (with adapters), and then gradually replace them with 2" (starting off with Ha).

But youre absolutely right, its mount first, camera second, optics last. It just happens that the 130pds fills a handy little niche, a reflector that fairly fast, cheap, a short focal length, and (just about) mechanically sound - though im not sure Mr Skywatcher had it in mind while building it that some nutter may want to shove a heavy CCD on it someday  :)

If tonight turns out to be hassle-free, I might change my mind about bringing it to SGL9..... which reminds me, I wonder how Lucksall is getting on - when I checked last time it was in danger of being flooded quite badly.

Edited by Uranium235

Share this post


Link to post
Share on other sites

That's a really good image, especially considering the conditions.  And beautifully smooth...

chris

Share this post


Link to post
Share on other sites

BTW, have a care with the gradient removal because I reckon there really is a significant assymetry in the outlying Ha. It's bugged me a few times. You need good flats as the only defence, really.

Olly

Share this post


Link to post
Share on other sites

BTW, have a care with the gradient removal because I reckon there really is a significant assymetry in the outlying Ha. It's bugged me a few times. You need good flats as the only defence, really.

Olly

Thanks Olly, I had a feeling I would be wiping out some genuine nebulosity when I flattened the background levels. Probably the best solution is to return in about a week and replace a portion of the subs (or just start again in 1x1!).

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.