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A quick look at the spectrum from this morning suggests the sodium emission is much weaker now. Colour images of the dust tail certainly look less ‘orange’ which maybe why the ion tail looks much more prominent(?). I initially put all this down to the poor seeing this morning but I think it’s real.
Will post images/spectra on my members site when I’ve had a closer look. Was also imaging Gyulbudaghian’s and Borisov’s VNe last night so a lot of images to plough through!!!
Mike.
A rather poor image attached taken at 07:04UT on 23rd May. Illustrates that robotic telescopes don’t always return excellent results! However, it is good enough to show that AL Com has faded significantly, as David’s photometry indicates, and is only just visible in this three minute exposure.
Mike
Hi Stewart,
The Gemini telescope is part of the Sierra stars observatory network (SSON). Have a look at their web site at: http://sierrastars.com/ . If you want to use it you will have to set up an account and then buy some credits. Then you can schedule jobs to look at whatever you want.
A word of caution though, as with most things you usually only see the good images. There are often ‘issues’ with using remote telescopes so don’t expect perfect results every time. Prepare for some disappointments…the image I downloaded this morning was rubbish!!!
Have you looked at iTelescope? They have a wide range of telescope sizes suited to all sorts of observing projects (SSON only have two 0.5M instruments). Payment there is with a monthly subscription but you can change the amount you pay on your ‘Plan’ quite easily.
Hope that helps,
Mike.
Hi Andrew,
You are right, the May image isn’t as good as the previous two, probably due to poorer seeing conditions. That’s why my post was more of a question than a statement and I have requested more images to confirm any fading. I think the trend is real but maybe exaggerated by the image quality.
More observations welcome!!!
Mike.
For the record my image of AL Com from earlier tonight. Had to image it well before astronomical twilight as cloud was forecast to come in off the North Sea…as it did just after the image was taken. The disadvantage of imaging from sea level in Suffolk and not from a mountain in Arizona!
And a couple of questions…
1) Is there any literature out there on AL Com? A quick ‘Google’ just came up with an Astrophysical Journal article from 1992 which didn’t really say very much.
2) And are all these observations being collected together for a VSS report or similar?
Mike
I can’t really claim any credit…it’s a great telescope! The UOI 0.5M Gemini telescope is part of the Sierra Stars Observatory Network (SSON) and was upgraded last summer. The new CCD makes images like this possible. The M88/AL Com image was a single 180 seconds exposure with a luminance filter. I’m no image processing expert; I just did a log stretch and a bit of stretching using IRIS to make the galaxy look nice(!). I took the magnitude estimate from the AAVSO web site where people like Gary report all their hard work.
Anyone can sign up to SSON and buy telescope time. They also have a 0.5M at Siding Spring to cover southern objects.
Mike.
My first chance to image AL Com was on 24th April using the 0.5M University of Iowa telescope in Arizona. It had already faded to mag. 14 in the 9 days since Martin’s image.
Is anyone else continuing to monitor/image this object? I’ll aim to take some more images in the coming week…
Mike.
I managed to get a ‘quick look’ spectrum last night as the clouds parted and before the nova went behind a tree!
I used my 4.5 inch F/5 Newtonian with a 12 degree objective prism to image a 2.5 x 1.3 degree field containing the nova. It stands out clearly from the other stars in the field. Even with my un-modified Canon 550D DSLR the red H alpha emission is clear and explains the red colour of the nova seen in other images.
The bright star at top right is mag. 5.6 SAO39688, spectral type A0, showing H beta and H gamma lines.
NLC display also well seen from Ipswich. I took a few shots with a hand held camera from an upstairs window!
This one was taken at approx. 3.45BST
Hi Andy,
Thanks for your comments. I’m learning Visual Spec as we speak! It’s good because it does the non-linear calibration of wavelength which is required when working with a prism.
Not sure I can make the Spectroscopy workshop in October…but hopefully there will be a DVD of the event…???
All the best, Mike
I thought it would be interesting to compare spectra of chi Cygni and mu cephei as they are both famous red stars.
I used the on loan BAA objective prism on my 12inch F/6.8 astrograph stopped to 4 inches and an un-modified Canon 550 DSLR. Despite the limited spectral range of the DSLR the spectra are clearly quite different. Comparison spectra are on the Orwell Astronomical Society forum:
http://forum.oasi.org.uk/download/file.php?id=393&mode=view
Only a quick look at this stage, I hope to get a CCD spectrum with the same set up in the next few weeks.
I also observed visually and chi Cygni was clearly visible to the naked eye. And through my 4 inch F/5 guide scope mu Cephei appeared to be redder than chi Cygni.
Mike.
My latest image of this southern variable nebula came through on Friday. When I compared it to one taken just 23 days earlier it was clear that there had been some small changes in the nebula. I re-processed both sets of images in the same way and then compared them side-by-side. The negative images below show the changes.
The central region has brightened but the small knots of nebulosity extending eastwards have faded. A bigger version is on the Orwell AS web forum: http://forum.oasi.org.uk/viewtopic.php?f=6&t=43
This object is certainly well worth observing regularly to monitor its long term behaviour.
Mike.
My latest image of MrG’s nebula shows that the eastern arm that was so prominent in the second half of 2013 is now fading. The nebula now has an appearance similar to that in the early part of last year.
Full sized image in the usual place…http://forum.oasi.org.uk/viewtopic.php?f=6&t=43&start=10 on the Orwell AS web forum.
Why not get out and observe this interesting little nebula? It is circumpolar from the UK at RA 20h 46m +67d 58m and associated with the star PV Cephei. But be warned…it is quite small and faint.
Mike.
My latest monthly image of MrG’s nebula is attached. The nebula continues in a stable state having had more or less the same appearance for the past 18 months. But it could change at any time so is well worth monitoring. The field of view of this image is ~ 10 x 10 arc minutes.
The full size image and all my previous attempts are on the Orwell Astronomical Society web page: http://forum.oasi.org.uk/viewforum.php?f=6
Mike.
Only one more image so far as the weather in Australia hasn’t been very good recently! This one is at the same scale, has the same orientation and the field star is also the same showing the motion of the planet. Triton rotates anti-clockwise in this view and has completed about 2/3 of an orbit.
More to follow when the weather improves!
Mike.
