skybadger

The missing link here is that the vixen adapter you link is meant to be used with dslrs and dismantled t-adapters. Sadly I have yet to find a «thing» to t2 male  thread adapter, they are all t2 female to camera native bayonet. So in the past I have made my own.

To attach a camera to the vixen draw tube I have  used a 60mm to t2 adapter or more preferably, a 60mm to M48 male to M48F to t2 M because it's more flexible for you to put a M48 filter wheel or OAG in between. 

OK then the answer is to use a t threaded t2 mount of any manufacturer and screw the t2 side into the camera while fastening the lens side of the t2 mount ring to the vixen adapter. 

On 24/10/2020 at 11:37, Stargazer33 said:

Bit of a zombie thread this one, but I've only just recently rediscovered it.

I've modified my original diy manually controlled focuser to #tekkydaves AAF2.

The focuser works great in Dave's test program and in APT; but it isn't recognised in N.I.N.A or FireCapture as they are 64 bit programs and the driver for AAF2 is 32 bit.

Having watched numerous YT videos about N.I.N.A.s autofocus feature, I would to give it a try. I would also like to use the focuser for when I do planetary imaging in FireCapture.

So, has anyone written a 64 bit driver for this focuser or know of someone who has and could point me to the download? If not I might try having a go at writing one myself; although I've never done any programming before! 

Checkout the ascom developer  forum on groups io .  IIRC you need to register the driver in 32 and 64 bit modes and may need to compile into any CPU mode rather than  dedicated architecture but many drivers do work without change. What does the diagnostics tool show when selecting as 32 or 64 bit ?

8 hours ago, Stargazer33 said:

Thanks Steve, I was looking at Robert's focuser before I stumbled on Dave's which I decided to go for as I could adapt my existing setup rather than start from scratch. 

As programs are moving into 64 bit, I just need an ascom driver for the AAF2 that will work with 64 bit versions of N.I.N.A. and FireCapture etc.

Windows takes care of that if registered properly, it doesn't matter whether it's 32  to 64 or any other combination. 

On 05/03/2021 at 21:30, Stargazer33 said:

The above no longer works as the latest release of Ascom v6.5 has removed the POTH hub!

I'm currently trying to learn how to rewrite tekky daves source code to enable users to enter the maximum step value in the ascom properties box and to enable it to work with 64 bit programs; but I wouldn't hold your breath! 

But the replacement hub does the same job with a different name!

IIRC, you take your canon t adapter apart by unscrewing the clamping screws at the side and mount the canon bayonet part on the smooth angled flange of the vixen adapter by tightening the screws up again. 

I'm just finishing building my own on a pulsar-like dome . The key benefits are that it is so much quieter, holds in place part open and does not slam into the end stops. It's taken a while to prove - it uses continuous steel wire around a winch bobbin and I still need to add a tensioner but mostly there. Largest cost is the motor at £140 and then some Arduino and motor control modules for wireless control. The wire is pennies and the guide wheels I made myself but can be obtained from Amazon equally nowadays. 

Like it !

I'll take a look there. Ta. 

Full well is 26 K e and the anti blooming gate should catch most of that unless really bright. What is the guide axis ? Ide be  looking at PEC or tracking first. 

Squeezed mine in when I did it last. 

I've been running mine for the last 6 months solid and it's been reliable. I use a led lens to concentrate the sky FOV onto the sensor. I compare with a portable unihedron and astap Sqm calibrator and it remains consistent. 

The problem with timers is the interval continually needs to change due to the changing alt, AZ movement rates. If you build yourself enough of a motor driver to drive the dome with switches, then you have enough to add the lesve dome control to for full dome auto control, or the velleman USB interface for the same. Both of these are open source on github or similar. Mines there too if you can do Arduino and some fairly simple soldering. 

Glad to see you got it working. I use the same library for my esp8266 encoder dome tracker. All gpio s on that chip bar one can be used as interrupts. 

It's quite hard to use the i2c expander to do this but there are dedicated chips to do this which you can interrogate via i2c and I believe the teensy has two internal encoder interfaces built in for free. 

But I use the same interrupts to directly measure pulse frequencies up to 200khz . 

4 hours ago, KP82 said:

The dew strips are designed to operate at 12V DC. If you plug them straight in the mains without any transformer, I believe they would just burn out (unless you make your own strips with appropriate wires I suppose). A dew controller can help control the power output so you don't overheat part of the tube causing air current.

I'd go for a 12V 10A supply instead of 5A just to be sure there is enough power.

You only need a few watts each,   so much less than 2A. 

Thanks Mike. It's not unsimilar to many other domes. A friction wheel driving on the  underneath of the dome rotation may do your job. Alternatively if your rotating internal or external profiles are round-ish, a motor could drive on that surface. 

My dome drives on the internal edge but still uses power and control electronics for the shutter motors which are powed from solar & battery and uses Wi-Fi to communicate with a central controller PC . Hence allowing continuous rotation and independent power. 

Either way, take a look at cytron power controllers from the likes of the robot parts websites, they are cheap and provide large currents for simple motor controls. 

Or maybe someone here can provide you an ascom compliant dome driver ?

There are numerous large motor drivers out there, some for less than a tenner, that will work directly from a bidirectional switch. My dome shutter manual override works like that. 

Hi Mike. As an engineer I will now say those important  words , what are your requirements ? If you can rotate in a circle , a number of motors (between 1 and many) are probably easier to implement. They could be friction, belt and pinion or some other method of engagement but there are numerous open source and off the shelf solutions for that which would means your skills requirement can be kept to the appropriate level. 

Any details on the dome and physical layout ?

I'll have a stab..

Calculate the local hour angle for the meridian at Istanbul at 12-3=9am .

Which star ? 

Ecliptic coords are ra and Dec ? 

Lower transition ,is that the same as upper and lower culmination for a polar star ?

IE need more details please. 

10 hours ago, han59 said:

The ASTAP measurment doesn't require an external calibration. After solving you can measure the "star flux/(2.51^magnitude)" ratio using the star database and this value will be constant.  Outliers  and saturated stars will be ignored. With the "star flux/(2.51^magnitude)" ratio you can precisely express the background signal in  magnitude per square arc second.

So this measurement doesn't need calibration. It is calibrated each time against a star database. Dirty optics or aging has no influence as with the Unihedron meter.

As long the CCD or CMOS sensor is linear it will work. Maybe the biggest problem is the signal reduction at the corners of the image but that can be compensated by applying a flat.  But probably not required due to averaging.  Above measurement was done without applying a flat.

Han

 

Agrees the stellar photometric way is the gold standard.it's just the way I read the post. 

I'm struggling to understand why the measurement is dependent on altitude,  your signals are relative between star and background at any altitude. Perhaps you are saying the sky is brighter further from zenith ?

Just to check- are you using the unihedron to calibrate ASTAP or the way I would expect, plate solving to calibrate the unihedron  ? 

Also, why are you using a x3 Barlow when the quark has its own x4 built in ?

On 18/01/2021 at 05:12, Florin Andrei said:

Ok, I'm probably doing something wrong. All I see is a smooth red ping-pong ball. No details. If there are any sunspots (right now there aren't any, but I've seen some in the past few weeks), I see them quite well. The edge is sharp enough. Basically, everything I see in the 50mm viewfinder which is equipped with a Baader solar film, I also see in the big scope, except it looks red.

I've done visual observations and even imaging before, in white light, during eclipses and the transit of Venus. I was able to capture enough detail and even some granulation in the camera. I'm new to H-alpha but not new to astronomy in general. Here's the total eclipse captured with this ED80 a few years ago:

This is the H-alpha system I've built this winter:

 

- Orion ED80 with a 60mm iris in front (not seen in the image) to keep f-ratio at f/30
- Moonlite 2.5" focuser - fresh install, replacing the original Orion focuser (it was time to upgrade anyway)
- Baader UV/IR cut filter (allows 656.28nm)
- Baader 3x telecentric (threaded into the focuser using a custom T adapter - no smooth bore couplings, it's all threaded)
- DayStar Quark Combo Chromosphere threaded into the telecentric (a 1.25" camera nosepiece installed backward serves as a T adapter)
- cheap diagonal
- GSO 0.5x focal reducer
- bunch of 1.25" extension tubes calculated to have the focal reducer actually operate at exactly 0.5x
- TeleVue Plossl 40mm

 

The Quark receives a cone of light at f/30 (D=60mm, F=1800mm). The reducer cuts that down to F=900mm. The magnification at the eyepiece is 22.5x.

I moved the tuning knob on the Quark through the whole range, tested every step. I always wait for the LED to turn green before I observe, which always takes a few minutes after each adjustment. Not a hint of detail anywhere that cannot be attributed to white light.

I've replaced the diagonal and the eyepiece with a 0.8x reducer and an APS-C camera, and I don't get any H-alpha detail there either - but I didn't try the whole range on the Quark tuning knob, only the center. I've captured 1000 frames and stacked them. These are the first 10 frames:

https://florinandrei-astrophoto.s3-us-west-1.amazonaws.com/halpha-no-detail.zip

The Quark is new, I bought it a couple months ago from an online astronomy shop.

Any suggestions? What should I try next?

Since I have no experience with hydrogen alpha, I don't know what to expect. Is the Sun so quiet these days that no details are visible for visual observations in a small aperture?

On mine I can see prominences without it being turned on. Solar disk detail becomes available with a low setting and solar self heating takes it past the tuned point so an erf is becoming essential . This is used with a SV80 Refractor so it's within the aperture range. Turn your heater settings right down and work through the range. 

To balance my dual rig I use an extra long hand clamp against one end of the dovetail on the scope and the other end on the far end of the dovetail clamp to slowly push the dovetails through their clamps, retighten, and iterate  until it balanced with axis clamps undone. The hand clamp addresses the high friction and weight on each dovetail, even when released enough to move. Otherwise I can't move them easily and smoothly by hand anymore. 

Measurement is possible by comparing motor current either side of the axis of interest. I haven't tried that yet though.

I recently had to do something similar for a M54 to M48 rotator - they are made and available overseas but by the time they are posted here the price is ugly and the delay is too. In the end I settled for making a M48-t2 rotator  - its a t2 adaptor with a M48 front thread and a t2 rear. Something I really thought I'd be able to get hold of. I'm lucky enough to be able to make my own but there needs to be a  place to get this sort of kit.