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Thanks Xilman. i believe i have the answer now. The secret is on the AIJ WCS settings page, where there is a tick box to constrain the search area to RA-Dec and the radius. Turn this off. Also uncheck the tick box to specify the pixel size. One should be able to specify this exactly, but turning it off works. I also entered the correct RA-DEC centre and constrained the search. The solves is lot quicker, as one might suppose. Hopefully im now in a position to solve any field in AIJ
Another hint is to start “Watch ansvr.log”. This runs in a cmd window. From this i was able to see the progress of the solve. Im sure you’r already up to speed on this, but i note it here for anyone else ascending the same incline !
Cheers…
Alex. thank for explaining some of the concepts.
If S/N was important, with hind-sight i would not have used a red filter. Of all the observations i count 5 instances of the use of an R filter. My data seemed OK (the READING light curve), but might have been better without the filter. The logic was to improve the seeing and so the resolution planet/moon.I made some rough notes which were useful to me at the time, but some of links are now unavailable. On the whole i believe we followed most of the good advice that was on offer.
As the occultation time approaches i see observers planning to observe on Occult-Watcher. This is good and i hope every one gets to see this remarkable event. But what will the maximum duration actual be? To find out we need observers on or near the mid line of the prediction. So anyone in the following areas would be helpful:
Redcar, Tadcaster, Castleford, Sheffield, Burton upon Trent, Solihull, Cirencester, Chippenham, Warminster, Weymouth and anywhere in between.
Good luck to everyone….
Thanks Alex for the reminder. Im looking forward to monitoring this long event. I am in the shadow and it could be one of the longest durations. We will see. My PB is a 29 second event. There is also the slim possibility of detecting a moon. The more observers there are, the better we can probe the space around Medea.
Good luck.I see on Denis’s images that JWST is about 3′ arc North of the HORIZONS position at my location in Oxfordshire. This is what my college maths gives me: (300/350,000) x 57.3 x 60 = 2.9′ ( Denis is 300 miles north of me). I don’t expect any prizes, but its good to exercise the brain cells from time to time.
The HB front cover of Constellations & How To Find Them (W. Peck) indicates the direction of JWST. Follow church spire up a bit and there it is. The only imaging i’ve done in 10 days !
Edit: Congratulations to Denis for some fine images on successive days, and good news (on 30th) that fuel reserves are greater than expected due to the excellent Ariane launch profile.
When i enter the info asked for i get a load of stuff about JWST in red, but no list. Is there a glitch with the system?
My thanks to the nine observers who indicated they would be attempting this, but were clouded out ! I had set up a second telescope (8″ F/4) in the garden to make a duplicate observation by video. This could be compared with the CMOS camera.
What i found were a few technical problems with the video setup, which I was able to correct. So this was helpful at least.
Tim
Richard/All, Good luck to everyone tonight. The weather forcaste over Oxfordshire has been variable, A day ago it was 100%cloud. Now only 15%. So i live in hope that I get a chance, and Moon light does not interfere.
Tim
These are good observations from our European friends. British observers were on chords near position (3) on the DAMIT shape model (see Link from Alex) where the duration was about 25 seconds. This area of the profile was sparsely covered as a result of obscuration by cloud.
I was clouded out and this is the same story for many. However there are a few lucky observers in Europe who got a clear view of the occultation. Thanks to all who peeped outside. There are few opportunities to see (2) Pallas occult a star of sufficient brightness. This was one of them.
There are many asteroids and many stars, and the best place to look for predictions for favourable event is Steve Preston’s pages: https://www.asteroidoccultation.com/
The Asteroids and Remote Planets Section will be pleased to receive your observations.
Tim
Great video – thanks for the link Alex,
For those who may inquire, why telescopes shine lights into the sky? Well from what i understand this is part of the adaptive optics feed-back system. It doesn’t effect the images. A wiki would be the best place to seek further info on this.
TimGrant: Yes, time dependent events like this are particularly prone to weather conditions. There are 25 observers across Europe, 7 in the UK that i know off. Best of luck to them all. A number of chords across the asteroid will help refine its shape. We have no direct imaging, and based on light curves its not spherical.
To update you Alex, i connected my QHY174m-GPS camera to a 50mm F/3.6 finder. This was from Orion Optics originally but suspect it is a standard design. The instrument was in the polar home position. I adjusted the three finder alignment screws to bring the pole star a bit nearer the center using an eyepiece, then plugged in the camera. The scope had been parked from the previous nights observing. I focused the camera and the pole star was at the edge of the CMOS field. Its not necessary to have the pole star detected though.
I went through the routine with ShapCap Pro which is well explained with on-screen popups. The offset was measured from the automatic plate solving as 7′ arc. This was from a drift alignment originally but i knew it was a bit off. Polar alignment plate solve is build into the routine. Then i moved the scope 90 degress in RA as requested by Sharpcap.
After making corrections to the alt/az screws the routine reported 1′ arc. I could have got a bit closer but reckoned I was at the limit of the adjustment screws on the mount. So i settled with this. Now the guiding is very good indeed and gotos are spot on.
Cheers..
Hi Alex,
Thank you for your reply. My solution was to set up a similar arrangement with the dew band around the C11 OTA, and a Celestron dew shield over the top. The Celestron dew shield is quite heavy, so your foam mat is a better idea. Im now using my Newtonian in a Pulsar 2.7m so dew is much less of a problem.Cheers –
I wasn’t aware there was an earthlier design. The 2.2m Pulsar dome is advertised to have the dome drive – apologies for the miss information.
I agree with Jeremy. I had considered exactly the same proposed setup as yourself, but concluded i wouldn’t fit in the dome with the scope 😉 However i suggest that a motorised dome rotation would overcome the narrow slit difficultly. It works very well on my 2.7m Pulsar. I align the aperture on the OTA, and select sidereal rate on the control box. The azimuth drive system can be retro fitted.
I also find the variable bright at r 12.88 +/-0.05 (Unfiltered CCD, GaiaDR2/Astrometrica). Poor conditions of drifting high cloud in Moonlight Measurement were from start, mid and end of a frame sequence at 5s intervals for 20min.
A web-cam on the finder is a useful arrangement. Since i already have a 9×50 finder and a suitable camera, i bought one of these from FLO: https://www.firstlightoptics.com/adapters/astro-essentials-sky-watcher-9×50-finder-to-t-adapter.html.
Agreed, Its helpfull to have some form of dark frame subtraction to remove hot-pixels if the web-cam is used with longer exposure settings. False stars can be confused with real ones !
