17 August 2016 at 3:18 pm #573594
Was out in observatory last night using my specto kit,Alpy 600/guide unit attached to an 80mm f6.8 triplet apo,and a diy classical design with 1200l/mm reflective grating attached to my C9.25 @ f6 all riding on an EQ6 pro,both spectroscopes use an Atik 314L. Target star was 34 Cygni (P Cygni),collected 10 frames each with both units and stacked,tilt adjusted and calibrated in the software BASS project.
Thank you for looking
Attachments:17 August 2016 at 7:26 pm #577471Robin LeadbeaterParticipant
That is an interesting setup. I have wondered myself if the guide unit (which can be the tricky part of a DIY spectrograph design) could be incorporated into other spectrograph designs. How did you couple the two together? Did you use the reflective slit from the ALPY?
EDIT: Ah sorry, rereading I see you have two separate spectrographs/telescopes. How are you guiding the DIY higher resolution setup?17 August 2016 at 8:04 pm #577472
Thank you,wanted to arrange a way in that I can take lo-res and hi-res in a session without the hassle of swopping out spectroscopes and re-arranging the counterweights etc. So I have the SCT carrying the hi-res unit and the 80mm taking the ALPY /guide unit on a side by side dual bar. Both scopes are aligned so I know that if star is center of ALPY slit then it will be in the slit of the hi res unit. Then I just guide as if I were using the ALPY,seems to work so far and I’ve managed 5min exposure times with no problems:)
Alun17 August 2016 at 8:27 pm #577473Andy WilsonKeymaster
Nice spectra! I’m interested to hear about your setup as that is something I had contemplated. A low res spectrograph on a small telescope, piggy backed on a larger telescope with a high res spectrograph. I thought getting the slits aligned would be just about impossible, so I’m very interested and impressed to see that you have achieved it.
Andy17 August 2016 at 9:08 pm #577474
Dual bar side by side to keep CofG low helps the EQ6 carry the kit with no problems (though scary bit is having to loosen lock nuts on mount head to shift all the kit whilst using one hand to hold the whole lot in place when sorting out the balance!). One of those Skywatcher guide scope mounts carries the 80/ALPY (just slightly over recommended capacity,so could do with one of the beefier baader units). Last night was first light for the rig and so far,so good:) Have attached a photo to explain better.
Alun17 August 2016 at 9:30 pm #577475Richard MilesParticipant
It would be good if some of this could be the basis of an article in the Observers’ Forum of the Journal, Alun. Something about the kit and a few examples of the resulting observations using your dual spectrograph. I haven’t seen anyone operating two systems in parallel before. Nice.18 August 2016 at 12:19 pm #577476
I will need a few more sessions to iron out any problems that may arise with the kit,(most of those are more likely coming from my DIY unit) But I would be more than happy to offer material for the Journal,thank you 🙂7 September 2016 at 9:40 pm #577482
Tonight was the last straw for attempting to use my dual scope/spectroscope setup. No matter how tight I bolted down the skywatcher guide scope mount,something would shift causing a mis-alignment of the slits. Even changed guide scope mount out for guide scope rings and that was even worse!:( Works great if working on a small area of sky,but any meridian flips etc causes a shift and I am spending more time re-aligning the slits than actual observing……So now back to C9.25 on the EQ6 and swopping out spectroscopes each session.7 September 2016 at 11:40 pm #577483Robin LeadbeaterParticipant
I have a second hand 2 inch flip mirror sitting in a box, bought on impulse after I saw Bernard Heathcote’s combined spectroscopy/imaging setup a few years ago. I still have vague ideas of mounting the LHIRES and the ALPY together on the C11. The Alpy would need a focal reducer though so there may be issues bringing them to focus, let alone ideally making them parfocal.
Robin9 September 2016 at 4:50 pm #577484
I don’t give up easily and hate failing,so have set up the rig again as per photo above. I have a feeling all the flexure was coming from the focuser on the Kson triplet,they are only held in place by a run or two of plumbers PTFE tape!! So have now bonded the focuser to the tube and have also beefed up the guidescope mount by adding a spring under alt adjuster. Fingers crossed everything holds position this time:)
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