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laser_jock99

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Posts posted by laser_jock99

  1. I've looked at buying this lens as a possible replacement for my ageing Nikon ED180 F2.8 which was the recomended fast widefield AP lens in its day.

    I don't want to hook it up to a CCD- so has anyone got any unprocessed, full frame DSLR images at F2 to post? I'd like to see if it is an improvement on the 'slow' old Nikon! And also how well it handles CA- one of the Nikons failings (on my lens at least) was issues with CA wide open. I found I had to stop down to F4 and use a Lumicom Minus Violet filter (almost half the cost I paid for the lens!!).

  2. 5 hours ago, old_eyes said:

    In my design, I have the roof sitting over the warm room to allow for lower side walls,

    I got round the need for having lower side walls by parking the scope in the 'upside down' position- I think I'm unique in doing this!

    40579240702_ec6db7b926_b.jpg

    • Like 1
  3. On 07/04/2019 at 15:40, wimvb said:

    The area where I'm building is old forrest ground on top of moraine. In short: roots and rocks. I managed to lift a few rocks out of the way, but then hit upon this monolith. Question is: will it do for a pier foundation? The rock is roughly 1.2 x 0.8 x 0.5 m and too heavy to move even with a bobcat excavator. Sweden is mostly bedrock with boulders of various sizes. Once you hit bedrock, it can't get more solid and stable, but even boulders of this size can move due to frost, which can go down as far as 0.5 m. The boulder definitely is not lying on top of bedrock, and if it can't be used, I will probably need to pour a foundation right next to it.

     

    You have my full sympathy. I hit bedrock within inches of the soil surface- but I still had several feet to go down, along a 12m long stretch of slope. It took months to get through!

    47528907502_48dd8c34a5_k.jpg

    47528904642_5d0e192de3_k.jpg

    Fortunately my biggest rock was only wheelbarrow size- at least I know the pier is concreted to the bedrock!!

    33704877388_ad5db5a5ec_k.jpg

     

    • Like 2
  4. On 08/04/2019 at 20:54, old_eyes said:

    I am thinking of using polyester coated corrugated steel as the cladding for as much as possible - I like the low maintenance aspects and it fits with the rural environment. There are sheds like that all over the place! Not sure of cladding for the asreas where the roof runs as corrugated steel would stick out too much. Possible half-timbered?

    Any immediate thoughts, particularly looking for the stupid mistakes that more experienced eyes immediately spot.

    Cheers!

    I used plastic coated, galvanised steel cladding on my obsy build- dark green to blend into the landscape. It seems to have weathered the storms okay and to be honest looks as good now as the day we put it up- no rust or detoioration to the finish. I'm in the process of planning another shed with same material.

    Timber frame

    47528591812_0d8930c62b_k.jpg

     

    Dark green, sheet metal walls fitted to frame.

    47528591192_b5dd724b4e_k.jpg

     

    Finshed off the two visible sides in waney edge pine cladding.

    47528590292_445181ce12_k.jpg

    • Like 2
  5. On 03/04/2019 at 15:13, mckinnell said:

    I am trying to gauge as to what is thought to be the best size of shed to use as an observatory; i shall as i have noted in other threads, my wanting to convert the standard pent roof style shed, in my own opinion being the best overall shape re removal of roof, BUT, am not to sure as to what the inner dimensions for the actual scope and mount would or should be need to be, as,  this would naturally impact the over all size of the shed proper, so, what would be the best as such size re shed for a NEQ6PRO 300PDS Skywatcher system, i understand if it seems to many as liken to a piece of string etc, but, i really do wish to get as many answers from any and all regarding this issue as it really will decide the area that i can use in relationship to the end build, if this makes any scence, hope so, if not, very sorry, but it's the best way i can put it,.

     

                                                                                                                                          Grateful thanks and regards to all,              Tom.

    In short- go for the biggest size 'shed' you're allowed. The 300PDS is a monster scope and once on a pier the eyepiece/camera could be as much as 9 feet off the ground when pointing up! So you'll need good access room all around for at least a seven step stepladder. I opted for 3m x 3m because the metal cladding wall material comes in 1m wide sheets.

    Here's what an F4 12" scope (i.e. shorter than yours) looks like in 3m x 3m obsy- I deliberately went big so I could store garden furniture/BBQ's etc in there as well.

    46039013995_493ee069cc_h.jpg

    • Like 2
  6. I can't advise you directly on Hawaii- but you've done the right thing by booking during New Moon (something often forgotten in the excitement of booking a holiday!).

    You might be able to see online where the best weather sites are (mountains often have 'wet' & 'dry' sides.

    Probably best though to contact a local Astronomy Society on the island for the better observing sites?

    https://www2.keck.hawaii.edu/whac/home.html

    Good luck.

     

  7. On 03/04/2019 at 16:11, Yawning Angel said:

    Looks great! Best of luck with it!!

    One thing I learned from a RoR build, Make sure the rails can't carry wet inside either on top or underneath. The best way would be to have a tiny degree of fall away from the scope room ? Both myself and @Astrokev had the same problem

     Alternativley- don't use U-channel at all. Use outward facing L-section. No problems with rain/leaves/snow/ice.

    You can see the L-section I used in this photo

    26273086759_ee7bdf77d6_b.jpg

    • Like 3
  8. On 31/03/2019 at 16:22, old_eyes said:

    So, this years' promise to myself is that this summer I will set up an observatory so that I can save a lot of the faffing around. I am hoping by publicly announcing my intention I will force myself to do it rather than think about it. I hope you will all keep me honest !?

    Do it! The amount of time it saves is immense, and if it does start to rain, packing up is quicker too. My obsy also doubles as a 'man cave' too- HiFi, radio shack, BBQ etc.

    There are some excelent builds in the DIY section- have a look. My only advice is to go as big as you can to allow for maximum flexibility.

  9. The SQM-L is a great idea although I found (in a dark sky site) the results were somewhat variable. Point it near the Milky Way or a brightish star and a 21.8 sky suddenly becomes a 20 sky- such is the sensitivty. In the urban setting they are more consitant. Your idea of taking multiple average readings is a good one. Long term it will also track if your sky is changing in any way. Keep going!

    • Like 1
  10. 10 hours ago, michael.h.f.wilkinson said:

    When I was a kid, there were some men on the moon, I recall vividly

     

    I reckon NASA are planning on going back to the moon. There are a few interesting NASA sponsered studies going on. My son will be working on project mathematically modeling the behavior of moon dust later this year.

    My personal theory is they need this information to make better CGI!

  11. 5 hours ago, mckinnell said:

    here in Rugby we are alas, sorely lacking in outlets that stock much in the way of practical materials, i know, i spent a weekend checking out the few companies we have and some were true plumbers and builders merchants, Rugby is the pit from beyond..............YUCKKKKKKKKKK.    lol lol lol..........

    This company in Rugby made both my steel tube piers from stock lengths of tube

    https://www.charleswatts.co.uk/

    The price was much less than some of the comercial piers availble. I also bought a of lot the hardware (e.g. 1m long M18 threaded bar to sink into the concrete) for my obsy project here.

    Another Rugby company I found usefull for the concreting operations at my observatory was Lemon Groundworks- good for re-bar etc.

    https://www.lemon-gs.co.uk/contacts

     

    My steel tube pier bolted to a block of concrete.

    44600155930_b5cc20ddb4_b.jpg

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