Forum Replies Created
-
Posts
-
Perhaps they want to know who is planning on turning up to avoid overcrowding?
I certainly wouldn’t relish sitting shoulder to shoulder with lots of people at present. I’m not planning on attending – other than via Zoom (if available) but would hope they would be advocating the wearing of masks…
Just a note to say that I finished an updated version.
It now works with all current Starlight USB cameras.
The big difference is that if more than one Starlight camera is attached, you get to choose which one will be used. That has the benefit that multiple instances of SXcon can be run to control up to 4 different cameras simultaneously.
Additionally, the configuration file changes mean you can have up to 4 alternate observing sites/gear setups. These are used to document the images better via the FITS header keywords (pixel size, long/lat, focal length etc).
Also, I improved the code internally to make it more robust to dodgy USB cables.
As before, anyone who wants to try the freeware code is welcome. Just email me.
Silly question, are there many TNOs etc below 20th mag that are uncertain in their orbits or are we thinking 20-21 mainly here?
Its also worth remembering – for astrometry certainly – that though a piece of software may say that a time given is the start, end or middle of an exposure it may not be as accurate as you would expect.
I recall some of the guys from Basingstoke society devising ingenious ways to determine how accurate the recorded time of a DSLR exposure was and finding not just the shutter/camera OS delay time, but also delays of more than a second in some commercial camera control software – which would play merry hell with NEO measurements.
The told the developers of one of the software packages, but they didn’t seem to care.
I was under the impression that the Apollo samples suggested that a significant portion of the lunar surface was formed from materials that were originally part of the Earth’s mantle. The lunar interior is rather harder to sample, though it does have a fascinating gravity field.
The magnetic fields are also very different.
As its water soluble I am hoping the rain over the next couple of days will flush some residue away away and beyond that I am hosing the joint to free up some of the debris left – even if it will wet every thing for a day or two. May have a bash with a cloth soaked with meths or white spirit. Its going to be a week or so until things are dry enough to try bonding again….
Just to clarify, it wasn’t the No Nonsense that failed drastically but a different brand. The No Nonsense sticks to about 75% of the gel coated dome but not all especially – where a thin coating. I really wonder if roughening with some emery paper or something similar might have provided a better key.
Thanks for the steer to Gorilla and DOW 785. Have been pondering one of the Soudals too.
I wonder if my mistake was in not sealing it with paint before the first rain.
I really had not expected the stuff to absorb the water under any circumstance – not the behaviour you would anticipate from a “sealant”. That sounds more like filler…
I had a couple of mirrors done by VCSM last winter/spring during the covid surge. I couldn’t call them speedy, but one of the mirrors had unusual coatings which took a while to remove.
New coatings look fine. Images seem clean.
They are on: http://www.scientificmirrors.co.uk/
An f/8 315mm in a 2.1m dome? That really is tight. Did you add tube counterweights to balance at the midpoint? How frequently did you need to tweak the dome position?
My dome certainly isn’t new, but in pretty good condition, so would prefer to avoid major surgery.
I have a plan for the dome motor – it will probably need a couple of attempts to get it right, but a solution is possible. Finding the time is another. In the autumn perhaps when the gardening duties are slackening off is best bet.
I need to spend some quality time with a Raspberry Pi to and some NEMA 23 motors too.
EDIT: Someone kindly pointed out that the 315mm is a Planewave CDK and comparable in length with a C14. Very nice bit of kit, but a bit out of my budget range. 🙂
I can certainly see a way of doing it with a couple of stepper motors/drives, a Raspberry Pi and after a small amount of dome bodging. The metal bashing is the tough bit. I think I have a plan for that but I may have to do 10 minute adjustments until then, which are not fun in the winter.
I certainly take the point that 11″ would be better. I rather fancied the RASA but the field of view is perhaps a bit big unless what you want is pretty extended nebulae – which isn’t quite me. I don’t know anyone who makes an 11″ f/4-f/5 Newt and a 250mm took too long to reach mag 20 for my taste.
More important is rats attacked the dome last night and tried to gnaw there way in through my lovingly applied mastic… Ho hum.
Small breaks in cloud from Broad Chalke near Salsibury. Got one or two tolerable pics. Very civilised time here: feet up, glasses on and a cup of tea in hand as we sat in deck chairs and gawped.
Not sure why I ended up with 2 copies of the Perl comment. But to clarify, it was in about 1996 when I was maintaining some astronomy code for a PPARC project called…. Starlink. Code that is still available for Linux.
Have fun with that. I never got over versions 4.99, 5.00 and 5.001 all giving different answers to one script I used. 🙂
I obviously misunderstood your intent. I thought cost and convenience to the user was everything. Several members, in response to your request, suggested a variety of approaches that you felt failed on cost grounds. I suggested an alternative approach that required only the purchase of a simple camera, a stick on bubble level and a bit more effort with the software driving the camera. No engineering required. That seemed the cheapest and simplest option for supporting the cash strapped beginner.
Also, I must apologise, I had not realised that when you grabbed a chunk of the image frame you resized it using a method that so badly affected the apparent performance. The dimmer stars are pretty poorly shown. You might want to use a bicubic spline or similar next time. See attached.
Yes, the image section you now supply is much nicer and, as it happens, the image solved with astrometry.net, so you could obviate the need for charts.
I look forward to seeing Roger‘s design hit the market place, but think the commercial mark up will probably take it above the cost of a new ZWO 120mm or the systems sold by Altair, unless made in bulk.
But we’re into vanishing returns here…
I think I would be a bit worried by that image. Those are first and second magnitude stars! What sort of exposure are you using there? The camera allegedly has a 60% QE and is only 8 bit, but is good for exposures up to 60s apparently. I’m kind of hoping that’s a 1/25th sec exposure, as I would really expect to see more than that.
On plate solving. Its the elegant way to solve the problem. A stick on spirit level is hardly a demanding set up and you don’t need to buy a finder as you just use the main scope and also don’t need to consult charts – so its a cheaper solution too.
