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Thanks for the pointers Robin. I’ll check out CB’s website.
I’d recognized the relationship of focusing wrt to star size, etc. It just takes a bit of practice!
One question if I may. I assume that if (and I say “IF”) my seeing is less that 3 arcsecs that will reduce the FWHM and hence the spread?
Regards
Tony
Nice one Steve. Do we need a shared site to deposit our attempts?
I’d love to do some bench-marking to test what I’m doing?
(That is using other observers’ images/ISIS files to see what I should be doing…
Regards
T
Thanks Andy. I know my early attempts suffer from CA.
At 235mm aperture at f6.3 I’ve never had the target star ‘disappear’ in the slit. I suspect it’s a function of image scale, focusing (psf) and threshold for the displayed image (?). Once I get these maximized I’ll concentrate on guiding to the point where I can hold that target where I want it.
It seems to be perverse that the smaller/fainter the target the less CA I’ll suffer – given accurate guiding.
Rgds
T
Andy,
Attached is a composite file containing several outputs (for the recent RX And data). The different types are obvious by their headers.
I’ve saved it as a Word docx file in order to upload it but it’s actually output as a txt file.
If you’re at the Spectro workshop I’ll have the software on my laptop and can walk you through if needed.
{Otherwise a web-share session?).
Let me know if you have any questions.
Regards
Tony
Will do Andy. I’ll run multiple format reports for the same data (easy to do) and will post tomorrow.
Rgds
T
An un-calibrated frame from last night. 60 sec in “V” from a lowly G3 (as my 460EX is still hooked up to my ALPY) but I managed an hour before the cloud rolled over. A bright sky but SNR was OK. AIP4WIN MMT gives Mv 13.300 (+/- 0.005), falling to 13.45 (+/- 0.05) using 9 ensemble stars, but notice the increase in error as the clouds hit.
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Hi Robin, Yes thanks, I did something similar by flashing a red torch into the scope whilst taking a sighting exposure. The slit showed up fine and I marked it with the PHD mask as suggested.
I’ve noticed a few shadows and elongated stars in exposures and the Lodestar field seems slightly offset. I guess that it’s simply down to the OAG mirror(s) alignment. I took a quick 15 sec exposure of M15 to ‘see what I could see’ and the attached frame clearly shows the dead space. Is that common or do I have to work on the alignment and focusing to perfect?
Regards
Tony
V.useful Robin many thanks. Received my Aply600 a couple of weeks ago and I’m familiarising myself with it – and with ISIS.
(Although at the moment I’m having more success with BASS).
I’ve ditched my QHY5 guider in favour of a Lodestar which seems up to the job. Its now a case of optimising the platform. C925 With 0.63fr and Atik460. Lots of success with brighter objects.
I can identify (and track) targets to the mags you outline but the biggest challenge is just finding the slit to put those faint objects in! Frustrating when you take a long exposure for a faint star only to find it’s not quite “in the grove”.
I’ll start posting ‘first efforts’ asap.
See you at the workshop later this month?
Regards
Tony
Andy,
Much appreciated. Thank you. I know I could simply have emailed you but since this is a new forum I guess others will have the same queries.
I’ve played with ISIS and it looks like it’ll repay the investment in time/effort. I’ll get BASS asap.
I already use PHD for long photometry runs.
I’m looking forward to that article next month. David alluded to it but it sounds much more substantial than I first thought.
I’ll hold off ’till then.
Regards
Tony.
