Sunday, 19 November 2017

Lunt 50 - Single Stack / Double Stack Comparison - 19th November

I've had my Lunt50 for a month or so now, but, at this time of year here in the UK it's never the best for observing with the low sun and less than ideal weather. I had first light proper last weekend, but in my enthusiasm lost all logic and reasoning and as a result never really ended up with an image I was 100% happy with through continually fiddling with the pressure tuner and double stack unit. Since then i'd given it some measured thought as to setting up the scope, and was ready for whenever the sun may reappear.

The weather forecast was not great for the weekend, but around Sunday lunchtime the clouds broke up a bit giving some transient gaps so I decided to setup and see if I could capture anything. Tuning the scope with some features on the disk was really easy compared to last weekends blank sun, and as a result I decided to get some images in single stack and double stack setup. I'm quite pleased with the performance in single stack, it reveals a lot more detail than my SM40 etalon would. SS image was at prime focus with the PGR CH3.

In previous threads and about the web there has been considerable discussion about the suitability of the LS50 as a scope for imaging in that people cannot reach focus. I struggled with the B600 that came with the scope, but the obvious solution was to use the Coronado BF15, this has much less optical length than the B600 and then reaching focus with a variety of configurations is possible. As an added benefit the BF15 lets through considerably more light than the B600 - I was getting 7ms DS 4ms SS with the B600, with the BF15 it is 1ms SS 3ms DS, quite a difference!

A side by side comparison of the black and white images:

Sunday, 12 November 2017

Ha Full Disk - 12th November

It has been some time coming; the full disks I was getting from my trusty DS40 came to an end last year when a slip de-contacted one of the etalons.  I was able to recontact it but I was never completely happy with the results, there was banding and an uneven field of view.  I purchased a 50mm double stack etalon around this time as it was a bargain price, and then only very recently got round to buying the Lunt50 scope to go with it - once you double stack you never go back!  Totally the wrong time of year with a very low sun and poor weather, not to mention the demise into solar minimum, but it is nice to get the full disk overview in Ha.

Conditions couldn't really have been much worse, a direct northerly wind meant the temperatures at 500mB were very low, meaning much instability in the atmosphere.  Throw in the 'Cheshire Gap' effect where the weather blows in straight in between the high ground of North Wales and the Peak District funneling clouds over the West Midlands, and the clear blue skies were just a wolf in sheep clothing.  This time of year the low sun has dropped into the trees from my yard, and I only have a some brief windows of branch free viewing in between the foliage, so I was keen to make the most of things.  

I'm not used to the pressure tuner system, let alone the double stack, but I was pleased with this result that I got at prime focus (350mm) with the DS50.  The camera was the PGR Chameleon 3.  Not much to see on the sun at the moment, the filaments appearing to be associated with the long distant relics of active regions of old.  Not sure how much use I will get out of the scope this winter, another year passes and the trees on my souther horizon get bigger meaning less viewing time.  I will certainly try though if blue skies present themselves.

Sunday, 5 November 2017

A Blank Sun To Start November...

The sun is very quiet at the moment, no spots at all, just a small relic patch of plage maybe indicative of an old active region?  Looking at the STEREO spacecraft data there is nothing on the way round in the week ahead either.  The joys of approaching solar minimum!