jambouk

Does anyone have a circuit diagram of the board inside the Skywatcher EQ8?

Can you put the mount on a trolley and just wheel it out? Or what about a pier and leave the mount permanently set up.

The skywatcher one will be fine for visual. It’s fine for imaging; I have the older version where the only issue is the tube can rotate so needed some anti slip material between the tube and the top of the tripod.

I found this video on the Pathe website of Frank Hyde’s radio observatory and also an interesting page about him on the St Osyth Museum website. I do love these old videos. https://www.britishpathe.com/video/VLVA6AQVJCU9X8HTEOYLHIALNF4RY-UK-ASTRONOMER/query/UK https://www.stosythmuseum.co.uk/people/frank-hyde

The paper has now been written and appeared in The Antiquarian Astronomer last summer: https://ui.adsabs.harvard.edu/abs/2021AntAs..15....2B/abstract

This book may interest those stamp collectors: https://www.amazon.co.uk/Stamping-Through-Astronomy-Renato-Dicati/dp/8847058457/ref=asc_df_8847058457/?tag=googshopuk-21&linkCode=df0&hvadid=334395561503&hvpos=&hvnetw=g&hvrand=17074239590385933949&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9046404&hvtargid=pla-655928454133&psc=1&th=1&psc=1

Can you share a video of the issue you have discovered?

Possibly. You could be the first lunar imager who has been thwarted by periodic error

With your DSO images, do you have the first sub and the last sub of a DSO imaging run and flick between those and see if the stars move.

Looking on astrometry.net and using those coordinates in Stellarium, I've worked out... If I turn tracking off in Stellarium the stars differ in the direction of the blue arrow. In my subs, the stars drift off in the direction of the yellow arrow, so I suspect it is imperfect polar alignment. The stack is a stack of 80 x 60 seconds so 80 minutes in total.

Unguided yes. Sorry.

Canon 6D at prime focus on a Celestron C14; unguided. 80 x 60 second exposures stacked without alignment. Is the drift mostly poor polar alignment? FoV is 32 arc minutes by 21 arcminutes, f/l 3910mm. (Ignore artefact bottom left and vignetting, no flats or darks used in this stack). Thanks. James.

Possible causes: - lunar tracking not selected - polar alignment not tight enough - kit not properly balanced - kit too heavy for mount I can’t imagine there is a problem with the firmware or the intrinsic lunar tracking rate.

An interim measure would be to stick some of these on the mount to stop the cable pulling out by taking slack out of the wire, +/- some blue tak over the joint, or a couple of small spots of hot glue to leave that end semi-permanently fixed. https://www.amazon.co.uk/SAF2-SELF-ADHESIVE-STICKY-HOOKS/dp/B007JV8VJU/ref=asc_df_B007JV8VJU/?tag=googshopuk-21&linkCode=df0&hvadid=309954504712&hvpos=&hvnetw=g&hvrand=14317359327806001109&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9046404&hvtargid=pla-696194517776&psc=1

Guide the cable with something like this:

Can’t you fix the existing cable? Just get polarity correct. James

Thank you. That seems to work. James

How do I make the font size of star names etc larger?

Does anyone have any recommendations of small wind turbines (200 to 600W I suppose) to trickle charge a 12v battery for an off-grid location? Already have solar for another battery so don't want to discuss solar here. Exposed and relatively windy location. My research suggests horizontally arranged blades are much more efficient than the lantern type (vertical) blades. Thanks. James

Thanks all. So is there a way to estimate the percentage dischrage of both batteries in this scenario? James

Assume I have two identical brand new 12v batteries, each with 200 amp hour capacity. One drives a 12v motor which pulls 60 amps and the motor is run for 5 minutes. The other battery is connected to a smaller motor which pulls just 5 amps but is run for 60 minutes. I'm assuming both batteries have discharged 5 amp-hours worth of their capacity (2.5%). Have both batteries really taken the same "hammering"? Thanks for any replies. James

I use an old laptop power supply and it delivers 15.5v I think.

The thermosphere and exosphere boundaries do not seem to be static, with changes induced by the varying pressure of the solar wind. Do changes in the strength of the solar wind result in alterations in the altitude of low earth satellites? James

We have a copy of this in the Library of the Society for the History of Astronomy, 1958. It seems it was written / edited by EW Playfair according to my notes. James

My set up, I adapted a laptop charger and soldered the leads together and it delivers 16v and 5amps and I’ve not had a problem with it.