globular

20 minutes ago, Louis D said:

The new APM SuperZoom is supposed to be easily usable with eyeglasses.  If they're back in stock for Christmas Eve delivery, I'll be asking Santa for one.

I agree it looks a lovely zoom for glasses wearers.  I'm a bit surprised at the price point though.  I guess with the hyped demand and limited supply it was inevitable. 

Thanks Robert (@Charlie 2436)

On 04/09/2020 at 14:54, Charlie 2436 said:

Thanks for the advice Michael. I guess I would be better going for the 9-27mm version, although the 7.2-21.5mm Would have suited me better.

While on the subject of eye relief does anyone know of any 82 degree eyepieces with good eye relief that don’t cost a small fortune.

Hi @Charlie 2436. 

Did you get the 9-27mm zoom?  How do you find it?

I have the 7-21mm version and it's 15mm eye relief is not enough for comfortable use with glasses.  I, like you back then, was wondering if the reported 18mm on the 9-27 make it glasses friendly?

3 minutes ago, Greymouser said:

@globular I have hardly used it the last few months, because I have hardly had any sessions, under the stars. To many other commitments; a very tired failing body and clouds. However, my view is still the same, it is a very good eyepiece and the figures sound about right, though I far from an expert. I have used very few zooms. Hope that helps. 

Many thanks 

On 04/04/2022 at 23:04, Greymouser said:

I have it and so far like it. Of course, I have not had enough use to come to a proper conclusion, but so far, so good.

As circumstance allows, ( Which is not all too often... ) I will use more and try to remember to report on it.

Hi @Greymouser

How have you found the 9-27mm zoom over the last few months?

Is the FOV really 40 to 60?  I have the similar looking Hyperflex 7-12 zoom (also claiming 40-60) but it measures more like 38 to 55 to me.

And how is eye relief?  The claimed 18mm (rather than the claimed 15mm of the 7-21) is the main thing that's caught my eye.  Is that about right do you think - i.e. a bit more than other similar zooms?

Ask a moderator Stu, they’re bound to know 😉

Stunning. 

@cajen2 How have you got on with this EP since?

3 minutes ago, MalcolmM said:

I thought they were on very long lead times everywhere!

From Baader's website ....

¿dn ʎɐʍ ʇɥƃᴉɹ ǝɥʇ sᴉ ʇxǝʇ ǝɥʇ ʇɐɥʇ oS

I have an Edge and they are locking bolts on my version.  

The idea is that you loosen them, focus, then tighten them again…to lock the mirror in it’s focused position…so that as the OTA moves during tracking / slewing you don’t suffer from mirror flop.

For imaging this is a big deal and nice to have.

For visual it’s not really necessary and I just loosen them at the start of the session and tighten them at the end before packing away.

If you’re on a PC then

• edit the post
• hold CTRL and right click the image
• select edit image
• change the pixel size to be 1/8 of whatever it is
• making sure keep aspect ratio is selected
• click update
• save your changes

If you’re on a phone or tablet then I think double tapping the image does bullet points 2 & 3 in one go.

4 minutes ago, Peter Drew said:

We had them specially made to fit 7" diameter seamless aluminium tubing.    🙂

Do you mean you made the tubing specially to fit your coffee tub lids? 😁

Maybe I'll stick a battery on the back of one of these...
https://smile.amazon.co.uk/Adeept-Compatible-Tracking-Ultrasonic-Processing/dp/B086HLJRDT 
... and tell it to keep to the front of the scope while avoiding the tripod legs and me.

19 minutes ago, DaveL59 said:

Ahh the simplest and cheapest ideas are so often the best, nice one! 🙂 

I was tempted to suggest the lazy susan idea but carrying the battery rather than using it as slip rings but decided that wasn't a great idea either.

Yeah I considered that too... but a large battery circling around the top of my tripod doesn't feel very convienient.  And I'd actually like to solve the cord wrap problem.... I could then feed power from a mains source too.

30 minutes ago, DaveL59 said:

From the source of everything we seek of course, Amazon 🙂

Available in many widths and no reason you couldn't wrap it over itself to improve wear resistance, esp if you buy the type that has conductive adhesive (usually called dual-side conductive or similar).

20 M Copper Foil Tape with Dual Conductive Strong Adhesive Copper Foil Tape for Guitar and EMI Shielding,Soldering,Electrical Repairs(30mm (W) x 20m (L)) : Amazon.co.uk: DIY & Tools

I guess you could even use it to fashion the wiper parts, using the copper tape to make the contact to the ring, tho a thin copper strip that's bent to suit would probably be better. How much current is this likely to be trying to draw across the foil/wiper as that may be an issue if there's not enough surface area/contact pressure?

 

I'm feeding power to one of these...
https://www.firstlightoptics.com/dew-prevention/lynx-astro-4-port-dew-controller.html
... so up to 10 Amps max @ 12v.  (In reality I'm nowhere near the max but would like to match the max rating if achievable).

The diameter of the circle needed is about 9" so a run of around 750mm is needed.

How do I calculate what width and thickness I'll need?

And my main issue is how to fashion a brush connector (that works in both directions) and how to hold it to maintain sufficient contact.

And how much drop off in voltage is there likely to be?

I'm all questions and no answers, unfortunately.

1 hour ago, Synchronicity said:

Lateral thinking - could you wrap the cable round anti-clockwise at the start of the night so that as the mount tracks it slowly unwinds?  At the end of the night you have the cable at what would normally be the start point.

Michael

Thanks Michael.  However it's not really a tracking issue (I'm not imaging for hours on end) it's a slewing to different targets issue (visual use) so I don't know which way I might be going from one moment to the next.  I usually think "where is the cable" before I do a big movement... but I'm bound to forget eventually.

But in any case, I'm trying, in this thread, to explore the possibility of a solution to the cord wrap problem - not work around or live with it.

10 hours ago, wulfrun said:

I'm not 100% sure of this but you can probably get copper tape, maybe even adhesive-backed. As long as it's a suitable size for the current involved. You could put it on something like pvc water pipe to make the support & diameter.  Then you'd just need a spring-copper strip to make a contact brush. Just some ideas to throw at you.

Thanks for the suggestions.  I have the same thoughts but just can't find appropriate parts in my google searching. I can see this ending up in a 3D printer purchase.... 🙃

1 hour ago, CraigT82 said:

If the weight of a larger battery pack on the mount is a problem could you go for a smaller and lighter weight battery pack, and buy another one spare to swap in when the first one runs out?

Good suggestion - but I quite like the idea of solving the cord wrap problem.  I'd probably forget to swap out the battery and lose my session to dew.

37 minutes ago, Dr_Ju_ju said:

Does the mount not do meridian flips ??  if it does then it 'should' reverse the movement direction, preventing cable snagging etc.

 

It's an Alt-Azimuth mount.  The anti cord wrap setting in software will amount to something similar - but I'm exploring the possibility of preventing cord wrap rather than living with it.

Thanks @wulfrun, I appreciate the reply.

I did attempt to search for copper slip rings of sufficient diameter - but rather unsuccessfully. They were either too small or rather over engineered (and hence expensive) for my low power low rotation speed needs.

Anyone know of something off the shelf more suitable as a starting point?  

I can put together and adapt parts someone else has made, but I don’t think my ‘knocking up’ skills run to copper slip rings.

Hi All,

Background waffle:
I have an Evolution mount that is powered by an onboard battery - so no cables to snag.  Tick.
However I also have other stuff (like dew bands) that I power separately using a single power cable to a controller mounted on the telescope, from where it's distributed to the devices.  It's all very neat and works well - but I'm left with a cable that will wind around the tripod if the mount slews round and round in the same direction.
There is a setting in the goto options that, when turned on, prevents the telescope from slewing more than 360 degrees.  But if you're at 359 and want to slew to 001 then it takes a while to go all the way round in the other direction - so I don't want to turn that on.  I could try mounting a battery up on the mount / telescope so that the battery and cable rotates with everything else - but the extra weight is problematic.  I could try tapping into the Evolution's power... but I've heard horror stories when doing this and I actually quite like the extra battery life of having a separate power source.  In all my time observing with this set-up I've just "kept an eye out" for the cable and repositioned it as needed without any incident so far - but I have had a few near misses and I'd like to try and eliminate the risk if it's doable.

Solution ?

I saw an aluminium lazy susan on amazon... https://www.amazon.co.uk/Lazy-Susan-Rotating-Aluminium-Turntable/dp/B07G4FY6VG?th=1 

It looks like this:

It's aluminium with steel balls... so maybe it will conduct power from the inner ring to the outer?

If I stack two of them... using the rubber feet to keep them apart... then I can feed both +ve and -ve through from the inner rings to the outer? So I've created a sort of power slip ring?

I then attach the inner ring(s) to the top of the tripod, just below the mount (in an insulated way so the tripod doesn't short it).

Attach the power source to the two fixed inner rings, and a cable from the outer rings to the controller mounted on the telescope.

As the mount rotates it will drag the outer rings with it - while the inner remain fixed.

So it can go round and round and round and the cable will never snag.

Some sort of insulating cover over it all to prevent any shocks or shorts when something comes into contact with it (and to make it look 'nice').

Job done?

What do you think?

[ Now we know why you pictured a colleague (expendable) using it on another thread. ]

1 hour ago, markse68 said:

Love your tripod (and your colleagues TeleVue flip flops).
Are they available or a Mark one-off?

If you want an Ethos 21mm, have you thought about the APM XWA 20mm 100 degree eyepiece?  It has 15mm eye relief and seems to get good reviews.
Sorry to extend your list. 🙃

3 hours ago, RobertI said:

Interesting that the mirror BVs only have 17mm aperture. Even so, I think l the absence of a GPC would still mean that a 16 mm eyepiece is getting me down to 45x which is more like was I was hoping for assuming the eyepiece has an decent FOV. Is that right?

Yes that's correct. 
A 16mm eyepiece with 60 degree fov will work just fine.
You may even just about get away with something like the APM UFF 18mm (giving your target 40x ?) but it will only fully illuminate 55 degrees of the 65 degree fov, so there will be some vignetting in the outer 10 degrees.  Some people report that they don't mind it, while others don't like it.

3 hours ago, RobertI said:

I literally only need a few more mm to get to focus with the 1.6x GPC but I just can’t see a way of doing it

Removing the nosepiece from your WO BV and directly screwing it to a diagonal instead will save you those precious few mm.
The Baader BVs (and some others too) have adapter options to achieve this.  You'd have to do some (scary) hacking to achieve it with the WO.
Or you could try without a diagonal.... might not be practical?

2 hours ago, Space Hopper said:

Maybe some do, but not all of them.

Do you mean the linear viewers like the Bresser ? That has a field stop of 22mm

Rob was asking about the Linear / Mirror Binoviewer "as sold by Bresser and under various other brands".

The Bresser are marketed as 22mm but:
1) people who own them and have measured them report they are actually around 17mm 
2) all the different brandings are actually the same design and most now accept and report them as 17mm 
(e.g. FLO's own StellaLyra version  https://www.firstlightoptics.com/binoviewers/stellalyra-125-linear-erect-image-binoviewer.html )

If you know of one that has been measured closer to 22mm I'd be very interested to know.