Zakalwe

Very, very clever.

It might be an idea to put some sort of guttering on the front edge of the lid. If there is any water on the edge then it might run down the overlap of felt and straight onto your scope? A piece of aluminium J-moulding would run it off to the side.

I'd use either Ethernet or an Ethernet-over-power cable. You will need power in the box (unless you are running DC to it?) and the Ethernet-over-power works very well. WiFi can be problematic and sometimes you just have to reboot it and fiddle about with it.

Your ingenuity amazes me!

You should go into business making these remote micro-obervatories!!!

Look at post 4 and 6 in this thread:

http://stargazerslounge.com/topic/219759-eqmod-through-eqdir-or-handset-pc-direct/#entry2361717

I go via the SynScan handset. I'm too much of a skinflint to buy the HiTech cable

Doing this can introduce signalling delays. EQMOD is designed to work with a direct connection to the mount, not through the handset.

When troubleshooting always try and remove as many variables as possible....perhaps the 20m cable and handset connection are part of the problem?

You have the DEC guiding output set the North. Change that to Auto and see what difference it makes.
Setting it to North (or South) means that PHD can only issue guide commands in one direction.

Yes, as far as I know John is still machining custom items. Our thread adapter for Daystar Quark was the result of a similar custom adapter he made for an SGL member. 

HTH, 

Steve 

Thanks for the reply.

I've dropped him an email for a custom ERF cell.

Is this service still available?

Neat solution! - I use one of these:

http://www.365astronomy.com/Amici-Prism-for-Polarscope.html

£110! Meep           

Those Seagull viewfinders are £30 off eBay. A couple of quid, some superglue, a bit plastic tube and some ingenuity and you will be £70 richer. I am in the wrong business!

http://www.amazon.co.uk/Seagull-Finder-Minolta-Olympus-cameras/dp/B004CGE90U

Or search for a 2nd hand Nikon viewfinder:

http://www.ebay.co.uk/itm/Nikon-angle-finder/351432521897?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D30773%26meid%3D563eda21fa0a437e9ef22dd48c8d4c69%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D251819848975&rt=nc

"Gravity" pure fiction ... ! ... next thing you'll be telling us is that "Interstellar" wasn't a documentary ... 

:grin:

ISS is a great one to watch for this effect. Take last nights high pass, potentially visible from horizon to horizon.

When it first appears in the west it seems almost stationary. Most of it's movement is towards you (radial). As it gets closer more of it's motion is across your line of sight (angular). When overhead or "abeam" (ISS never goes overhead up here) all its motion is angular. You see the full effect of it's 17000 miles per hour orbital velocity.

As it recedes everything is in reverse. Until eventually it's almost stationary as it fades on your easterly horizon. 

The change in apparent speed is smooth and steady. Nothing to do with flight dynamics or anything. It's entirely a visual perspective effect.

Should an object change its apparent speed abruptly or change it's path in any way it is almost certainly within the atmosphere under powered flight. 

The only orbital parameter that the space shuttle could change significantly whilst in orbit was it's altitude (and thus its orbital period). To rendezvous with ISS the shuttle had to be launched in a fairly narrow window  as ISS's orbital plane passed overhead. The shuttle was then effectively fired at it like a bullet. All the directional adjustments to ensure correct orbital insertion were done with the engines while in the atmosphere. Once in orbit all the shuttle had to do, and could do, was  play catch up and dock. Then to come home, it would turn blunt end forwards and fire its thrusters in the direction of travel to "de-orbit" . Again, no significant directional control was possible until back in the atmosphere when aerodynamics came into play and the wings did all the work.

These limitations (on any orbiting craft) are why the crew of Space Shuttle Columbia could not take refuge on ISS even if they had been aware of the damaged wing on that fateful mission. That flight was not in ISS's orbital plane and there was no way of getting there.  

Great post Paul (and a good explanation of why the film Gravity is based on pure fiction). Orbital movements are very counter-intuitive and to change an orbit requires huge amounts of fuel, certainly to make a significant change. Changing an orbit to the extent that it would be visible to an observer on the ground would probably be impossible.

what speed does the x-37 do in low orbit? if that is even known?

there will be no records for its activitys available.

Speed in orbit will be determined by height and mass.

Wikipedia gives its orbital speed as 28,000Km/h

And an imperial thread gauge. Celestron kit seems to have a mixed bag of metric and Imperial threads in their kit.

Personally i would not use Allen keys. A good quality set of 3/8" or 1/4" hex socket tools tend to fit better and do less damage to the heads. Teng or Halfords Professional are very good value and last well.

Allen keys, hex heads and screwdrivers are all considered consumable items. They wear out in a surprisingly short time and will start to round. You usually discover this late at night when the last bolt to be opened for that "10 minute job" rounds off.

Could it be something top secret, possible, who knows, but I would think it would'nt be doing more than the low thousands of mph in the atmosphere.

and you would'nt want it to be reflective for sure.

There'd be a hell of a sonic boom if that was the case.

From some of the other forums I frequent there is much (unsubstantiated) speculation on all manner of non-listed military orbital stuff.  Guess one point would be on what would need to be orbiting at that estimated velocity.

Unless it is powered, then it can only orbit as fast as orbital mechanics will allow. No faster, no slower.

To fix the problem (as your mount has encoders), set a park position in EQMOD (CW down, OTA vertical or horizontal).  manually move the scope to that point. Expand EQMOD and hit ReSynch encoders. That will align EQMOD to the encoders in the mount.

If the synch position is too far from where EQMOD *thinks* the scope is pointing, then it won't accept the synch. Look into the message centre (by clicking the + key) to see if this is the case.

This is why an obsy scope is "Parked" each night...it gives the system a known starting point. if you are setting up each night, then you'd use a rough Park position...for example I used to use counterweights down, OTA horizontal.

Much cheaper to buy proper astro CCD cameras

Judging by the number of trashed DSLR sensors on this thread, I'd say the same about de-Bayering!

Hi,

Just wondering if you had done any more testing with the DV-7000?

Hi there,

I only had one chance to test it (the first clear night in ages,,with a New Moon and I was away! grrrr ).

Unfortunately, I mad a mess of the focus, but this shows that the tracking was spot on. 80 seconds exposure at 70mm. 70/200f4L lens on a 1000d camera. I shot 50 frames and everyone was bang on (apart from cocking the focus up!)

Plus the Star Adventurer has settings for panoramic photography. It can also act as a basic intervalometer with the addition of a simple cable.

I had a very quick test of mine last night from my urban, light-polluted back garden.

I mounted a Canon 50D (with extra battery grip) and a Samyang 14mm f2.8 lens (also a first light for this lens). I bodged a counterweight using a long 8mm bolt and a counterweight off another portable rig. The whole ensemble was mounted on a fairly wobbly Manfrotto 190 aluminium tripod. A cheap eBay intervalometer was used to set 30 x 1 minute exposures. Polar alignment was fairly rough and ready, just using a phone app to get the approx. Polaris position. To be fair, a 14mm lens is never going to stress the PA!

First thoughts:

1. You are never, ever going to PA this thing and then mount the camera afterwards. There's just too much movement in the tripod for that.
2. The clip on polarscope light is rubbish. I need to come up with a way to attach it when the L-bracket camera head is mounted. There's a decent sized slot in the bracket to give an unobstructed view if you use a counterweight  to slide the bracket out of the way. I',m sure niothing nire than a bit of velcro will sort this bit out.
3. I have no idea of how to set the polar alignment using the date circles. The manual is, at least, confusing. Being used to robotic mounts, having to start polar aligning by scrabbling around on the ground, peering through a poxy polarscope made me feel like a blooming caveman. Give me technology anyday!
4. Using the locking clutch will almost certainly move the PA.
5. A half decent tripod is a must for this thing. I've ordered a Velbon DV-7000 to see if that's a bit sturdier and will report back on this when it arrives. The DV-7000 is supposed to be a fairly sturdy little tripod of under £90.

The results aren't going to win any prizes. This is the stacked image straight out of DSS with no post processing. The camera was pointed in the general direction Cygnus, though I paid no real attention to where it finally ended up. All the subs were fine, so the little mount had no problem here.

The Samyang lens looks pretty good, with half decent star shapes (the focus could be better, mind). There seems to be a pretty severe off-centre vignette. Some flats would sort that though.

Next steps:

1. Test a better tripod.
2. Test it with my 70/200mm f4 lens. This will give a much better idea of what the mount is capable of.
3. Make a right angled viewer for the polarscope. I have a couple of RA viewers for camera viewfinders kicking around. I might be able to bodge one of them on.
4. I wonder if I can extract the polarscope and replace it? I have a pretty expensive (for what it is) Losmandy polarscope, which has a superb polar alignment method. It'd be great if that could fit into the mount.
5. I have no idea how to process extreme wide-fields in PS. I had better do some reading!

Star Adventurer

Great progress and skills!

This is probably a daft question, but you can fit that box through the door, can't you?

Placed on order for one from FLO. Looking forward to receiving it.

 I had to repaint mine white to match the mount ;-) )

The one that I bought was in white....

A BMW is more like a 10 micron than a synta. Sadly when materials fail and contamination is discovered during the fix and a lack of support or information is a available this reflects on the whole. But its still fair value for money.

I' sure the mount will work all the better for a strip and clean, synta's always do.

Even a Jawa can be knackered by taking it apart without the correct tools and procedures.

I hope that you get it sorted. I know only too well (from years of messing with motorbikes) that sinking feeling of "I'll just nip this up another touch" and feeling the threads strip. :sad: