Forum Replies Created
-
Posts
-
Hi,
Thanks for the info. I bought an assortment of bits before GMN even went live (this was after and IMC a few years back) and thought I’d put something together but the road to hell….
So focused on developing the spectroscopy it was soon forgotten about, I recently found a couple of tiny board lenses in a box which prompted my question after seeing your pic. Might get around to it one day! ; – ))
cheers,
Bill.Callum,
Is your image from a GMN system? What is the camera/lens configuration are you using?
Cheers,
Bill.Hi,
After checking this evening I only got another 2 Lyrids from last night but there was a decent fireball on the HD systems from the previous night.
I got the zero order on another camera… just.
I can’t guarantee it’s a Lyrid so I’ll say “suspected” for the moment. However comparing to previous Lyrid spectra it looks like it’s one.Cheers,
Bill.Hi,
Thanks for the ongoing feed back. Mike, no I didn’t keep any of the short exposure images that I was taking whilst finding Vega to test my latest system.
As with comments Robin made, Vega was low to my NE at the time but the image you post is pretty much what drew my attention to the star, with extinction it even looked a touch brighter when compared to Vega at that point in time.
I’ll now use it as a guide post when reviewing my meteor images!
Cheers,
Bill.Hi,
Thanks for the info, also very interesting. I didn’t take any specific measurements as that was not what I was interested in but it was sufficiently bright to catch my attention.
Just a curiosity for me.
Cheers,
Bill.Hi,
Very interesting, It was just startling bright in the unfiltered ccd image.
I’ll keep an eye out for any meteor captures that have it in frame.
Bill.OK… there were 4 images attached!
Here they are again!Hi,
I was testing out the camera I’ll be using in my next meteor camera system and thought it would be a good idea to check what’s going on with T CrB.
This is a single 5 second unguided exposure, binned 2×2, cropped, linear stretch and re-sized. Taken 2024 04 09 23 46 58 BST. I found a finder chart on line but I’m not 100% sure if T CrB is bright enough to be visible.
I’ve circled what I think might be T CrB. The brightest star is Epsilon CrB for orientation. Does anyone have an image with T CrB in it to compare?
cheers,
Bill.Attachments:
Hi,
I’m not an expert on such things but given our “continuous” montitoring and timestamped images it might be interesting to see how it develops it we get a couple of lucky catches.
Bill.Hi,
Not monitoring purposefully but I like to keep an eye out for anything that might crop up in the background…
A fortuitously placed meteor right next to CrB but no sign of the outburst yet…
Cheers,
Bill.Attachments:
Finally inspiration!
As my old apprentice master would say “…aye, experience, one thing ye canny buy in the shops…” and how true..
Having obtained several more very high resolution spectra of varying kinds it suddenly occurred to me what was going on with this one.
I was also pretty sure that there was an order division but as I was expecting the distinct pattern of atmospheric near IR emissions toward the right of the spectrum, the lines present threw me off track a bit, However your division there was spot on. The issue seems to have been I bumped the focus! When this image is compared to my later ones it is clear this is the case.
Also, one of the other secondary pieces of information that can be gleaned from the spectrum image is that since the 2nd order are so clearly present it indicates that the meteor must have been a slow one. (As well as being rich in Fe lines!) Otherwise these lines would have been overlaid or masked by the pattern of near IR emissions from the atmosphere.
A bit rough and ready but it now all makes sense. Another mystery finally resolved!
Cheers,
Bill.
Hi,
ahhh, I meant “secondary” as in some sort of corrector not a secondary mirror… Even a “perfect” mirror will exhibit some aberrations at f2. Something to stretch it out to f4 maybe, a barlow lens basically, then the camera. I’ve got boxes of lenses to play with that I’ve accumulated over the years. However I have a small fibre fed Littrow spectroscope I built a while back sitting in a drawer. It needs a bit of tlc but offers interesting possibilities. Ultimately the mirror might just become a flux collector rather than a “telescope”, no need to worry about imaging quality then. The next problem is a suitable mount, it is a chunky piece of glass…
It’s all good fun!
Bill.
Hi, Grant/Eric,
thanks for the comments. I’ve used Galvoptics before but they, like Scientific Mirrors are a bit too far south for an easy drive. I’m a regular visitor to Manchester so Orion is not to much further down the M6. I’m always nervous when it comes to shipping big optics. Couriers will promise the earth but “…it fell off the forklift…” has happened to me before!
cheers,
Bill.
Hi,
Thanks all for the various comments. I don’t think I’ll be opting for any fancy coatings as I don’t know how good the mirror actually is nor how I’ll be able to fully exploit such a fast mirror without other aberrations being corrected.
Even if the figure isn’t that good, plain aluminium will do to let me play around with secondary optics with at least usable results.
Might be the worlds shortest dobsonian… ; – ))
I’ll keep you posted!
cheers,
Bill.
Hi Eric,
LOL, Exactly! I had just returned to Uni when it came out. My first copy, which was the hardback version, fell to pieces I used it so much. Currently have a paperback copy and also not for sale ; – ))
Indeed, this one seems to cover the more modern digital side of things but a lot of it seems to be optics and personal profiles which I’m not so into, got far too many books on optics and telescope design!!!
It’s looks like and updated take on the Solar Astronomy Handbook by Beck, Hilbrecht, Reinsch and Volker (Willamann Bell 1995). Also excellent but with the sad demise of Willmann Bell probably only available second hand, although some dealers may have a new copy or two…
I think I’ll give this one a miss at the moment but I think I’ll go and have a wee peek, suitably filtered of course, at the sun this afternoon while the sky is clear(ish)
Cheers,
Bill.
Hi,
Looks interesting… I may be preaching to the converted, as the saying goes, but for me the solar bible will always be Astrophysics of the Sun by Harold Zirin.
First printed in 1988 by CUP, re-printed 1989, it’s a bit dated but it is an excellent science foundation, graduate level but with much for the knowledgeable amateur. Only available second hand now and it seems to be sought after, some of the recent prices I’ve seen are very steep! However If you come across a decent copy at a reasonable price then I’d recommend buying it.
Cheers,
Bill.
