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Hi all,
Here’s my updated magnitude plot as of last night (12/13 June).
Cheers
Ian.Attachments:
Perhaps a longer series of measurements at a very wide range of magnitudes (from 7 to 17 perhaps) of a standard field (likely a Landolt field) may be mre informative.
Thanks Paul,
I’ve been reading about the Landolt fields in the AAVSO Transformation process. I think I’ll try and give it a shot…
Cheers
Ian.Good morning,
Attached is my updated graph up to last night (8/9 June).
The B-V settled at +0.29
Cheers
Ian.Attachments:
Thanks for your excellent imaging and analysis of the supernova. I was wondering, how you manage to get so much data, my skies are quite cloudy and even quite windy.
Also how do you find the M101 so accurately, which software and platesolving software do you use ?Hi Kwong,
Well, I have to say that I cannot remember a clear spell like the one we are having here in the UK at the moment! I don’t want to jinx it but it has been clear almost every night for weeks! I also have a remote observatory in Spain but the weather there has been terrible for weeks!
I acquire my images using software called Sequence Generator Pro. This does all of the scheduling for my imaging runs and I use PlateSolve2 or ASTAP for my platesolving:
https://www.hnsky.org/astap.htm
https://planewave.com/download/platesolve2/Cheers
IanMorning!
Here’s my updated mag. graph with last night’s results.
B-V now +0.28Cheers
Ian.Attachments:
I’ve added last night’s data (2/3 June) – see attached graph.
B-V = +0.26
Cheers
Ian.Attachments:
Any explanation for the drop in blue magnitude?
Yes, as Andy has explained – cooling.
Ian.Here’s my latest graph including last night’s results (31st May). I make B-V = +0.24.
Ian.Attachments:
Hi Grant,
I own 3 of those SX Midi wheels and also a larger one for 2″ filters and I have only had the droop issue when I was connecting one to a small WO71 APO with a fairly heavy ATIK CCD. I think it was the CCD that did most of the drooping in that case!
The other scopes I use have much more robust focusers such as Moonlite on my C9.25, and the Tak focuser on my Tak 85. These focusers are designed to carry much heavier loads.
I don’t think that the SX Midi FW is a particularly heavy example of a filter wheel, so I don’t think I can say anything that will help with your current setup. I think I would have to fall in the ‘buy another focuser’ camp!
Cheers
Ian.Good morning all,
See the attached for the graph of my continuing nightly R, V and B measurements. The continuing drop in blue magnitude is fascinating. B-V was +0.18 last night.
Cheers
Ian.Attachments:
Today’s update attached.
Cheers
Ian.Attachments:
Yes my spectrum from last night shows it cooling further to a black body temperature of ~12000K and a fit to an A3v star continuum with a B-V = +0.1
Here’s today’s RVB magnitude plot. The cooling clearly visible with the latest point B-V = +0.12.
Attachments:
That’s useful. The continuum in my spectrum from last night does indeed match an A0v star which by definition has B=V=R
Thanks for the info Robin, most interesting. I’ve attached my graph again – updated with last night’s points. It seems that the R and B are slowly swapping dominance! Also note the very slight dimming.
Ian.
Attachments:
It’s definitely plateaued
Here are my mags from last night (24th May around 22:30)
V = 11.03
B = 11.04
R = 10.99Cheers
Ian.Attachments:
How do you calculate its magnitude please ?
This is not an easy question to answer! I would recommend reading the AAVSO photometry guide which is kept well up to date:
As to the choice of software, I can personally recommend the Tycho Tracker software. The Pro version is well worth the $50 for the licence and is very easy to get going with. There are plenty of YouTube videos to get you started. Many will say to use AstroImageJ (which is free) but I think this is hard to get going with. I also use the amazing (and underrated) AstroArt8 software which is easily scriptable.
https://www.tycho-tracker.com/
Hope that helps.
IanWhat is the V filter I read on earlier?
I want to do photometry on this. Do you need a really high focal length telescope e.g. C11 or can you do it with smaller lower focal length refractors?
Can you use a h-alpha filter 7nm bandwidth and do useful photometry ? as I am in a light pollution area.You can use smaller telescopes – I regularly use a 100mm refractor to measure stars down to 13th magnitude.
The V filter is a Johnson/Cousins V Filter. These are standard photometric filters. You can still work unfiltered or use a colour R, G or B filter as long as you specify which was used.
I don’t believe you would have much success with a narrowband filter.
Hope that helps
IanHi all,
Very fractionally brighter again last night but looks to be flattening off. These from 22:30 UTC last night:
V = 11.04
B = 11.00
R = 11.02Cheers
Ian.Hi all,
Here are my magnitudes from 23:00 UTC (center) last night. Averaged from 10 measurements with each filter using 120s exposures:
V = 11.09
B = 11.06
R = 11.11So a full magnitude brighter than 2 nights ago. Attached is the current light-curve from the BAA photometry database.
Attachments:
Here’s my LRVB colour version from last night. I’ve uploaded R, V and B mags to the Photometry Database.
Best Regards
Ian.Attachments:
