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westmarch

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Posts posted by westmarch

    Is it worth the trouble?

    in Observing - Deep Sky

    Posted · Edited by westmarch

    Very sensible suggestion from Peter.  For visual, darker skies will usually give you more returns than many improvements in EPs or filters. It depends of course on what you are hoping to see.  There is little improvement on planetary targets or double stars but DSOs are very dark sky dependent.

    John

    How quickly does muck normally accumulate on dob mirrors?

    in Getting Started Equipment Help and Advice

    Posted

    Hi Pete,

    After getting mine second hand I washed the primary using mild soapy water and rinsed with distilled water and it came up fine - there are a few Youtube vids to assist. 

    I used to store the scope in the dining room because of the same anxiety about muck and mildew but my wife got fed up with that. I have since moved it to the garage with very little increase in crud accumulation.  Of course, not all garages are equal and muck accumulation phobia may be replaced by accidental damage anxiety. 😁 It does make cooling down quicker though.

    Like you, I have a truss dob and store it with a cap on the mirror,  another on top of the open end and the light shroud on. It does take a lot of muck to affect the visual performance so I try not to get too worried about it.

    John

    • Thanks 1

    10” Equatorial Platform for Dummies

    in DIY Astronomer

    Posted · Edited by westmarch
    slang

    22 hours ago, Jim-Lad said:

    Hello John,

    I love the simplicity of your instructions and it has given me the confidence to have a go at building as per your design. I've ordered some of the parts today but I am unsure what size (height, length) the aluminium segments should be as the printed size does not seem to match correctly with the top board when I print off the template (probably my printer settings) - If they are 200m in length then that's fine - I can work out the height, otherwise could you let me know what the recommended dimensions are?

    Many thanks,  Jim

     

    Hi Jim,

    i’ve just gone out and measured my segments., the length is 170mm.  To be honest I just printed Reiner’s segments off and made sure that the right angled edge was lined up with the top of the board and the start of the 20 degree angle on the board. The length of the segment will change depending on your latitude.

    Blind faith is a marvellous thing.  As they say in Yorkshire, “It’l be reet”.

    John

    Fuzzy hunting

    in Observing - Reports

    Posted · Edited by westmarch
    spelling

    1 hour ago, Stardaze said:

    Superb John 😀

    I might add to my Virgo list using some of those. ClearOutside has changed again here; 2 days ago, tonight looked to be as good as it gets, but now very patchy. Thursday may be my best opportunity to take the dob for a drive. We’re having a family day out today and I might take the scenic drive back to recce the spot I have been thinking of. 

    How dark is your spot? I’m in a bortle 5 here but 20 mins drive south gets me into a 4.

    Hi there,

    I’m Bortle 5 here and used to go to a public dark sky centre in the Yorkshire Moors but a Racehorse owner built a stable next door to it with horizontal floodlights, to keep away thieves.  Like you, I have found a Bortle 4 spot  a short drive away where I can park up with a fairly flat and unobstructed horizon.

    Good luck with your recce - I used this map to short list some spots and google street view to suss out parking before visiting.

    https://www.lightpollutionmap.info/#zoom=6.39&lat=54.4132&lon=-3.0354&layers=B0TFFFFFFFFFFFFFFFF

    John

    • Like 1

    Fuzzy hunting

    in Observing - Reports

    Posted · Edited by westmarch
    spelling

    There are some nights when it all just comes together.  Local dark sky site, moonless night, excellent seeing and transparency, dry with a low dew point, Virgo and Coma high in the sky and enough night hours to leisurely scan their galaxy clusters.  The kit all worked, I hadn’t left the illuminated reticle or the red spot finder on last time out, so the batteries were good.  The equatorial platform performed flawlessly, meaning that by the time you consulted Sky Safari, the star hopping point you were at had not moved out of the field of view.  

    Four hours spent teasing detail out of Virgo galaxies I had missed in the past and the Coma Berenices galaxies.  Main EPs were Explore Scientific 68o 20, 15 and 12mm.

    M61  Identified as a faint round fuzzy. No real detail visible but bright core on direct vision.

    M49  Mistook this for a star but fuzzy edges gave it away. Accessory star visible adjacent to it.

    NGC 4526   Identified as a faint oval fuzzy, a short star hop from M49.

    NGC 4762  Faint but clear vertical needle shaped fuzzy with a bright core, in direct vision

    NGC 5248  Tried but could not find this one.

    M91  Faint circular shaped fuzzy with brighter core on averted vision.

    M99 Struggled to find this.  Fainter than expected with brighter core in averted vision.

    M85 Faint oval smudge. No detail seen.

    M64 Black Eye Galaxy  Bright oval fuzzy with some core detail visible in averted vision. 

    NGC 4494  Found while star hopping. Faint smudge with brighter core in averted vision.

    NGC 4565 Needle Galaxy  Spectacular edge on galaxy - one of the highlights of the evening. Distinct bright central bulge with possible detail of dust lane and well defined, extended arms.

    NGC 4631 Whale Galaxy  Difficulty star hopping to this one, probably because it was so high in the sky.  Elongated but asymmetrical fuzzy.  Benefits from time taken to tease out detail. 

    NGC 5005 Getting cold by this point.  Struggled with directing the dob but finally found it. Faint elliptical smudge in averted vision with brighter core. Could not identify company  NCG 5003.

    That last one was almost vertically overhead, so the movement of the dob wasn’t intuitive and it seemed to have a mind of its own. Consequently I whacked my eye against the eyepiece and this morning have a bruise coming up.  Poetic really, the Black Eye Galaxy session leaves a reminder all of its own! 🧐

    Very enjoyable session. Sky Safari comes into its own as a planning tool, a log of the session and when shifting between finder star hopping and upside down, back to front, EP star hopping.  

    Thanks once again for motivating me.

    John

    • Like 2

    Fuzzy hunting

    in Observing - Reports

    Posted

    11 hours ago, Stardaze said:

    There was a break in cloud just after dusk for a few hours and so I grabbed the opportunity until midnight, being off from work too this week. Meteoblue had the seeing down as poor and so I confirmed that whilst realigning my finder scope. I think it did improve a little throughout the session but it wasn't great. Thanks to @Pixiesfor the SkySafari star hopping tip, worked a treat at the eyepiece last night, I seemed to get my eye into the finder scope much better tonight.

    Started working upwards from Vindmiatrix.

    M60 - Nice a distinct.

    M59 - Similar to M60, both stand out well as a good starting point.

    M58 - Notably lower in brightness than M59, no detail.

    Virgo A - Seemed brighter last week from memory?

    Markarian's Chain - I sketched this out from memory when I got back in to compare as it's my first near full chain viewed (must download SkySafari Plus later as there's only 2 galaxies noted on the basic version). M84 and M86 were easy to find, like previously. NGC 4435 & NGC 4438 stood out together quite well and I found the bottom end after a minute or so (NGC 4473 & NGC 4477) but I really had to sit there for a few minutes to wean out NGC 4461, but no sign of a companion tonight.

    M99 (Coma Pinwheel) - Certainly spread out without a bright core to it. 

    M98 - Another one ticked off.

    M100 - Wasn't a great view but I was most pleased with the hunt and my ability tonight to find these in succession.

    M3 - Didn't resolve as well as last week, stars still lacking contrast even at x157.

    Melotte 111 - Observed this in the bino's early evening. Looked pretty good in the 10x50's.

    M51 - I was dying to drop in on my old favourite, now very close to zenith. I spent two stints searching hard for some structure, I could see the nebulosity around the core more clearly one side than the other but no separation. 

    M101 - Location of the Pinwheel always seems simple up to the last couple of degrees, following the line from Mizar. It's the first time this year I have stopped by here. Because of how dim she appears tonight I over ran it to begin with, but once found, she was extremely dim. On paper, much brighter than M51 at mag 7.86 (brighter than most observed tonight) but assume the area must be less condensed and so there wasn't much to see and report.

    M81 & M82 - First time here too this year for me. One of my 'go-to's' from last year and I'd remembered @Stuposting a simple location hop recently, which worked a treat. Both stood out well and I felt that transparency had improved a little, or maybe that I had relaxed off and had my eye slightly more adapted? 

    Some cloud was starting to roll in from the West and with temperature now at -1C I decided to pack up and reflect on what I felt was a more organised evening. Tuesday looks the best of the forecasts this week so fingers crossed.

     

    You've inspired me to get the dob out tonight and head to my local dark sky spot.  Time for some galaxy hunting around Coma Berenices.  It looks like a cold but clear night in Yorkshire.

    Many thanks.

     

    John

    • Like 1

    Skywatcher Dobsonians?

    in Getting Started Equipment Help and Advice

    Posted

    Hi there,

    you might also consider a second hand 250mm Dob. Most are either well looked after or have been rarely used.  If the main mirror is in good nick, any other problems are relatively easy to fix (the folks here are  very willing and able to advise). That might help you stay in budget, get the most aperture and leave something over for eyepieces.

    Hope you find something that suits.

    John

    10” Equatorial Platform for Dummies

    in DIY Astronomer

    Posted

    On 02/06/2018 at 22:12, westmarch said:

    After good advice on equatorial platforms from Moonshane and reading his trial and error progress to mastery, I finally took the plunge.  

    I lost the plot on how to work out the centre of gravity of my setup - see the last pic and you will understand why! - and assumed that the design would cope with common commercial 10” Dobs. (Don’t try this at home with a home build, bespoke Dob!)

    I opted for Reiner Vogel’s  excellent design for a VNS (Vertical North Segment) platform, mainly because I lack the trigonometry to calculate my own curve for the bearing and he has templates for various latitudes.  The thin aluminium arc also worked for me since it only needed a hacksaw and I also lack the woodworking skills (and equipment) to cut the inclined woden arc required for a circular segment design.

    Reiner’s general VNS guidance:

     http://www.reinervogel.net/index_e.html?/Plattform/plattform_VNS_e.html

    Specific design for the smaller platform:  

    http://www.reinervogel.net/Plattform/Vorlage Plattform 14 hoch.pdf

    I dispensed with the need to have the upper platform as the Dob’s turntable base and just sat my Dob on it.

    I couldn’t cope with the electronics and so am indebted to Nick Hill’s design for a motor - he just bought a direct drive EQ1 9v DC motor, widely available commercially from Celestron, Meade, etc. designed to move a telescope rig at equatorial speeds.

    Some plywood and a saw had the bases constructed.  Four 18mm pillow bearings and a length of 18mm steel shaft, an aluminium plate for the curves, aluminium right angle brackets for the attachments and an aluminium block for the pivot bearing were all that was needed.  (Isn’t ebay a marvellous thing!) Oh, and various screws, nuts and bolts.

    In all, it’s cost me £85 but you could save £15 on the motor if you got a standard EQ1 motor (they are all made in China and it looks identical but without the Meade/Celestron trade mark on it.)

    Haven’t had a clear night since finishing it but the motor is moving the platform, the stops prevent it from coming off the bearings and the Dob azimuth brake is able to cope with maximum tilt.

    Oh for a clear night to try it out! ?

    John

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    IMG_4445.JPG

    IMG_4446.JPG

    IMG_4449.JPG

    IMG_4451.JPG

    Following requests from a number of members I have attached more detailed instructions on how to build this equatorial platform. Including a correction of a typo in the original post correcting 8mm for 18mm bearings.

    I hope it is of some help.

    John

    Equatorial Platform Basic Guidelines.pdf

    • Like 2
    • Thanks 5

    Apollo 11 landing site

    in Getting Started With Observing

    Posted · Edited by westmarch

    21 hours ago, Moonshed said:

     if we can see galaxies at the very edge of the universe billions of light years away why can’t we see objects on the Moon that’s only 240,000 miles away? I try to explain about resolving power and so on but may as well talk to a budgie. 

     

     

     

    At least budgies know enough not to try try to argue about fundamental physics.

    John

    • Haha 1
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