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.


  • Content Count

  • Joined

  • Last visited

Community Reputation

124 Excellent


About ardbeg74

  • Rank
    Star Forming

Profile Information

  • Gender
    Not Telling
  • Location
  1. Hi All, Well had my first attempt at widefield with a DSLR the other night. All because of this article in the register... http://www.theregister.co.uk/2015/08/04/nearby_exoplanets_circle_nakedeyevisible_star/ Not sure why I felt compelled to image it, perhaps there is something magical about looking at a star and *knowing* it has planets rather than wondering if it does. Anyways I'm glad I did because I had a lot of fun.. its been too long since i last spent some quality time out in the garden. The set up was a bit precarious to say the least... i set the 3-2 up and polar aligned as usual, then stuck on the dovetail with the tube rings from the ED80 and screwed the DSLR onto the 1/4" which is on one of the rings. Wouldn't make a habit of this but thought... just this once. Finding the target was a bit strange, nada on liveview ( had it linked up to pc ) then after some test shots i thought the image was somehow upside down because there were bits of tree on the top right of the image... this had me stumped (sorry) Then i realised IT WAS THE TREES AT THE OTHER SIDE OF THE GARDEN. Oh my! 18mm is really wide!! Focus was a bit fiddly without a bahtinov and nothing on liveview, lots of test shots and tiny tweaks... you know the drill. Eventually i managed to get the target framed and in focus and a bit of experimentation with exposure. I opted for 30sec ISO 800, took 20 lights and 11 darks. Was lazy and didnt take bias or flats. Stacked in dss and processed in PI then some lines etc in gimp and a quite aggressive crop. Yea i know it not a great image, but it was fun and i guess functional Couple of things i came away with.. 1) I really need a LP filter, really really. 2) 18mm on an EF-S 18-55 lens is not very flat! I thought I'd knocked out my pa at first, then i realised it was fine in the middle. 3) Not taking flats was stupid. PI rescued me this time but... 4) I need a better way to attach the camera. ( Just took delivery of a star adventurer today so thats sorted and im now portable ) Anyways I had a hoot out there and can't wait to get back out... Any suggestions, tips, criticisms welcome on what i should be trying out / doing to make things better always welcome. cheers Mark
  2. On the Bahtinov, it works on jupiters moons too. Though im using the ASI when i do it, I see no reason it would't work with a DSLR, couple of sec exposure, max iso ought to do it. Once you find where the focus is, a pencil line on the focuser tube will get you close next time. Cheers Mark
  3. Hi Roger, Its an excellent tutorial mate, very easy to follow and im chuffed with the results. Nice colour scheme too, feels very natural unlike my previous attempts Appreciate the time you put into it, just another reason why the SGL community is so special. Cheers Mark
  4. Chucking it down all day today, i hope the summer isnt over yet Worked through Rogers tutorial after dinner tonight. Had a lot of fun with this though registax 5 was being a bit temperamental and throwing out of memory and floating point errors. But i was throwing tiffs at it. Though it was fine with jpg's. Stacking worked well, ive never used the ROI feature before so that was good to learn too. Thanks again guys, see you on the solar section. Cheers Mark
  5. Thanks for the tutorial David. I'll have a read after dinner. Sure was a strange experience seeing my garden in the daytime Cheers Mark
  6. Well its 1200mm on an eq 3-2. Most of the problem is wind i think. The PL is essentially a huge wind sail and it generates enough torque to flex the eq head. Also any vibration such as walking near the scope ruins subs too. Balance is also an issue, particularly near the zenith as i have to be very careful not to let the ota bang into the mount legs, so that sometimes means not being as balanced as i would like. Not knocking it though, its great visual and planetary it will hold the target in a 300px box quite happily. When i first got my polar scope i thought i was getting 60sec, but on close examination the stars were elongated. 10 or 15sec subs mean a gazillion files to stack so the compromise is 20 to 25 sec. Im not annoyed about this, Its not an imaging set up and i never intended to get into AP. It just kinda happened. As far as im concerned everything ive done to date is just proof of concept. The big question was, Is it worth trying to image in london? To which the answer is OH YES! It sure is. So its time for the NEQ6 and hopefully i'll be throwing away the odd sub like you and keeping the rest. Cheers Mark
  7. Baader solar film arrived during the week and I got some time today to make the filter cell. Armed with an assortment of cardboard, glue, packing tape and double sided sticky tape i set too. Organised chaos at the dining room table but the end result. One snug fitting, sturdy, full aperture solar filter. And it was sunny outside to boot. One thing i did forget though, laptop screens are hard to see in sunshine. So i stuck the laptop in a large cardboard box and stuck my head in there too, which made focusing pretty awkward. Some sort of telescope screen required i think I had been curious about how to get aligned properly, but found a great tip online, use the shadow of the telescope as a guide. Shortest shadow is pretty much bang on. Sure enough it works a treat. I did take a run of 30 subs at various iso / exposures... pic posted is 1 sub @ iso 100 1/1200 sec. But i had a little problem when i tried to stack in AS!2. It crops the image to 2400x2400. Im not sure if reducing the image size before hand is a good idea. Is there any other free software which will handle large images or should i just go ahead and reduce the image? Cheers Mark
  8. Hi Jd, THREE SUBS!!! out of 217 I think i get 3 that are good, 30% junk and the rest... well i'd rather junk em but then i'd have nothing The move to a more stable platform is going to be very welcome indeed I dont think thats an exaggeration, check out this site: http://www.pbase.com/samirkharusi/image/37608572 He has a lot of other great articles too. I need to re-read this, i read a ton of stuff like this when its cloudy, but promptly forget it all when the dust cap comes off. I remember trying to figure out the sky glow using his method, but the clouds appeared. Based on slightly dodgy results i estimated around 17.5 mag/sq arc-sec. So very long integration times indeed. which is fair enough, but i cant be doing with dropping half my data cos its bad. For m51 i decided on 9 hours... i got 1hr 8min so far, 2 sessions i junked because of bad flats / poor transparency. The other 2 session were not so bad. But it certainly aint easy in uk skies, thats for sure Cheers Mark
  9. Yep got you on that. I actually used iso1600 on the ring. Im usually 800, but transparency was good and the test at 1600 seemed ok, so i went for it. Hopefully it will be ok tonight, going to gave a proper go at drift alignment. If i can push it up to 30sec then i'll be chuffed.
  10. Wow thats a cracking image you got there Jd! Those colours are amazing!! Did you use a modded DSLR along with the CLS for that? Or is this the cls coupled with longer integration? Whats amazing is that you did this at 2.7m and got great results using 30sec subs. This is all very encouraging. How are you finding the eq6 at that FL, are you loosing many subs or is it just a few here and there? Cheers Mark
  11. Thanks again for the processing advice Olly, I'll be brushing up on my ps skills then, starting with the selection tools for one and no more blanket sharpens either! Best thing is, i can go back to all the other things i've imaged and apply what i've learned to them too. A definite win win situation Cheers for that! Im constantly surprised by whats possible in heavy LP. Looking up at that orange/purple sky with its 20 or so visible stars you would be tempted just to go back inside and watch tv or whatever. Sticking an EP in doesnt help much for fuzzies, 45min looking at M1 and not seeing it was the start and end of my messier bagging experience. Dark adaption, pah! i dunno what it is, can read outside. I mean, other galaxies??? Have a tough time seeing the galaxy i live in. But stick a camera on and open the shutter for 20 sec and the universe pops out. Im totally hooked. Hopefully at some point this year i'll be guiding and we will see whether a cls is required and how badly the lp limits exposure time. I'll keep you posted. About the ring.... this from wikipedia: All the interior parts of this nebula have a blue-green tinge that is caused by the doubly ionized oxygen emission lines at 495.7 and 500.7 nm. These observed so-called "forbidden lines" occur only in conditions of very low density containing a few atoms per cubic centimeter. In the outer region of the ring, part of the reddish hue is caused by hydrogenemission at 656.3 nm, forming part of the Balmer series of lines. Forbidden lines of ionized nitrogen or [N II] contributes to the reddishness at 654.8 and 658.3 nm. Is this a valid narrowband target? Cheers Mark
  12. That makes sense, dunno why i thought i would get longer. Though in theory i wont have to throw away so many subs which is good. Looks like i'll have to go down the guiding route earlier than expected. But have the ASI cam so can try the finder scope method maybe. More stuff to research I did take a look at the DARV method actually, I like the idea of it but yes it does seem like a fiddle and more time away from getting subs. Having said that, if im throwing away half my subs and not happy with the other half then its not time wasted. Cheers Mark
  13. Thanks for your kind comments guys! Olly, thanks for the processing advice! Ive now reprocessed it, hopefully i got it right. I aligned the channels in the histogram just using the black point. Background wasnt near 23 so then i made adjustments to the mid point until the 11x11 sample was around 23 in all channels for the area i intended to crop. BIt of despeckle and unsharp mask. Cropped then reduced by 50%. Seem to be getting a lot of colour noise so maybe i stretched it too far? Anyways it doesn't look red now. Very dark in laptop but ok on my monitor. Really need to download one of those colour / contrast chart things. Alex, thanks, yes i use photoshop. Ive heard good things about GXtermitator, i think i'll stop sitting on the fence and just buy it! Now that the vignetting issues are fixed and my flats arnt killing my images ( managed to create a flat with TWO peak areas ??? ) Im finding that im left with nasty gradients... Theres something im wondering about, anybody care to guess how long an exposure i'd get unguided at 1200mm fl on an neq6? and what about the addition of a 2x barlow? how long could i get with that? Im pretty close to buying the neq6, probably next month. Gave up trying to decide whether to buy another scope, i dont really know what direction im going in so just going to use the PL until im sure. Curious about what to expect exposure time wise? Cheers Mark
  14. Thanks Guys,Yes! I believe the centre star is in fact the one that caused that lovely display. Just a little hot core giving off a lot of energy. Seem to remember something bout square laws and surface area vs luminosity or something. So i guess it must be really hot, or perhaps not that far away. I really should research my targets more No light pollution filter. Have considered a cls clip but that would require longer exposures which i probably wouldnt achieve. I dont have any direct light pollution though just sky glow. Now that ive sorted out the flats ( before they were destroying my data) im just left with gradients. Especially when the moon is lurking behind a bush.I agree about the PA, i think its a combination of bad balance and wind ( need to cut down on the cabbage before an imaging session ) There are a few subs that are perfect. THe finder isnt perfectly aligned though, it has slipped off centre, but not by much. No its down to the demands im putting on the mount at my FL i think.Just for giggles, here is my my M51. IIRC its 1hr8m of 25sec subs ( that took a while to stack )Pretty much just sticking my toe in the water with the equipment i have to see if its worth investing in a proper imaging rig. But i do wonder what will happen when i try longer exposures at a shorter FL??? Will my skies hold up?CheersMark
  15. Quick process of Saturday nights attempt at the ring nebula. Turned out to be fairly easy to find though i could only get a hint that something was in the EP. A quick exposure at max iso revealed that i was dead on target ( for once ). It was smaller than i expected, almost tempting to barlow it, but not with my setup This was about 18min integration, 56 x 20sec iso 1600, 30 dark, 30 bias, 20 flat, 20 dark flats. I think i must have nudged / upset the polar finder alignment because i really struggled to get even 20 sec without some trailing, and even with that the stars arn't as round as i would expect for such short subs. Was originally 80 subs but had to drop a few. Background looks a lot more red now that ive uploaded it too... anyways just glad to have gotten something with a hint of colour. I never really expect to get anything in London skies, but even with a non imaging setup and no clue of what im doing, its just great to get some hint of whats out there. Suggestions, tips, thrown eggs welcome as always Cheers Mark
  • Create New...

Important Information

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