Avocette

16 minutes ago, Captain Scarlet said:

Just this minute delivered by postwoman, an extender for my az-gti . Funny, when the az-gti arrived it was much bigger than I was expecting. And this pillar is much smaller than I expected!

anyway, many thanks to @heliumstar!

Magnus

 

I could have told you the size - taller than a mug of tea or coffee, but clearly shorter than a bottle of wine…..

The differences (AFAIK) between the AZGTi and the AZGTe are that the AZGTi has the auxiliary encoders (‘Freedom Find’) which most of us turn off when doing AP, but also clutches on both axes which with an EQ wedge become the RA and Dec axes. The AZGTe lacks one clutch, missing from what becomes the RA axis, which for me, is pretty important when you’re setting up the ‘home’ position with the telescope pointing towards the North Celestial Pole (less than a degree from the Pole star).

Both mounts can be bought packaged alongside various telescopes. For use the mounts hold the telescope in a standard ‘dovetail’ clamp, fixed with a knob bolt.

Hi Mike and Dave,

Thanks for your great work on GHS! I've been working with your scripts on and off over a couple of months, and am very impressed with the concepts, and since v2.2.0 especially, the implementation and UI. I watched your TAIC presentation and am keen to continue building my knowledge and experience of the use of the script. Is there an obvious place where 'beginners' can ask embarrassingly simple/stupid questions please? I thought you might have a GHS forum over on GHSAstro.co.uk but I see you refer there to the PI and SGL forums.

In the couple of years since I began my astrophotography journey using various software, it was your TAIC lecture which first drew my attention in detail to what stretching an image does to the data. Your explanation of how we can control and develop the contrast in an image, whilst protecting against crushing bright areas or clipping image data at the dark end of the histogram, caused a real 'eureka' moment for me! You've set me reworking a number of my images, albeit slowly and step by step.....

My first 'dumb' question is about the dark end of the histogram. When I look in detail at one of my typical image stacks, there is a flat line for a good distance along the horizontal axis where there are, apparently, no image pixels. I presume that this is due to the offset I have set in my capture program. I use ZWO ASI533MC and ASI2600MC cameras at the recommended offset value of 50. So should it not be possible to detach the hyperbolic curve from the graph origin and shift the attachment point axis along to the right to the point just before the first image samples? in this way you would not be wasting useful output image values for image brightnesses where there are no pixel samples...    

Thanks in anticipation for putting me straight on this or for pointing me in the right direction....

Ed

PS Also posted on the PI forum

On 16/06/2022 at 20:56, alacant said:

The mirror is then held in the cell using silicone.

Any particular type of silicone? Are we talking about construction silicone rather than bath sealant?

I’m thinking of doing this with my SW 150p (not PDS). If I remember well I have read on this site that the secondary mirrors on the two 150 types are the same size, unlike the 200PDS and the 200p.

Curious to know how much it cost to hire the remote observatory for this? I’m struggling against the low altitude atmospheric dispersion and streetlamp light pollution from my home (Bortle 5ish)……

10 hours ago, TerraC said:

 

Careful if you are flashing this.  At the moment the Dual mode EQ firmware link on the skywatcher site points to the regular ALT-AZ firmware by mistake.   Reports are coming through of people flashing it and losing EQ mode and having to flash back to 3.38. 

Ray

 

 

It looks like SW have just reissued v3.39 for AZ/EQ use (dated 10/6/2022).

I own both APP and PI. My choice these days is to use APP to load Lights, Darks, Flats, Dark Flats, perform Tab 3 Star Analysis to check the quality of my images (useful graphing functions) and then Tab 6 Integration to stack the best of them using the default settings. I use the Tools Tab 9 to Crop the result to get rid of dither edge effects, and then Tools Tab 9 Light Pollution Removal which is absolutely brilliant. Often I save a stretched version of this image as a jpeg to share directly with friends and that may satisfy me at least temporarily, especially if I’m keen on capturing more images of the target. I save all the final integration, crop and light pollution removed images as FITS files. When I am ready to carry out more processing, I import one or other of these FITS files into PI to make use of more delicate control with star removal as an option and also noise reduction. I am experimenting with GHS in PI.

The 150PDS is f5 (750/150) and the modified focal length depends on the the specific coma corrector you use. There are coma correctors which don’t modify the focal length and others which do. The Sky-Watcher least expensive one has a x0.9 focal length multiplier action so 750mm reduces to 675mm.

On 02/05/2022 at 09:49, Ian McCallum said:

I've been using the Raspberry Pi with Astroberry for a number of months now, but I'm having some communication difficulties with Wi-Fi.  I've read that using a USB 3 thumb drive in one of the USB 3 ports can cause problems with the on-board Wi-Fi………..

I think there is a slight confusion here - the known ‘problem’ is potential interference between the USB3 circuitry, ports and 2.4GHz WiFi. You may avoid this with Astroberry by forcing the WiFi hotspot to use only the 5GHz band. I run two Astroberrys in Flirc metal cases with the underside plastic panel outwards away from mount metalwork to give minimum restriction to the printed circuit WiFi antennas. The systems work simultaneously close by each other, both exclusively using the 5GHz band, controlled by a laptop outside during polar alignment and from inside the house at a distance of about 8m afterwards. I use Samsung 256GB Fit Plus USB3.1 drives in place of micro SD cards. I pick up lots of other WiFi networks when setting up and selecting the Astroberry hotspot networks (with different SSIDs) on the laptop.

I think I’ve made some further progress! This advert shows the FR/FF already with the (unmarked) spacer ring in place.

https://www.365astronomy.com/TS-2-PHOTOLINE-0.8x-Reducer-Field-Flattener-for-70mm-and-80mm-ED-Refractors-from-f-6-to-f-8

So it seems that with the 8mm spacer ring removed the FR/FF may be directly suitable for a 70mm ED refractor………

40 minutes ago, Anthonyexmouth said:

Surely just a specific adapter that changes the thread size, Probably the "for ED80" is just there to say its for some specific ed80 that had those threads. You'll just need whatever adpater it is that threads onto your drawtube and converts it to the FF/R

Not quite since it is an 8mm thick solid spacer tube with M42 male thread on one side, M42 female thread the other. It fits on the camera thread end of the FR/FF. The threads on the other end of the FR/FF are around 50mm (possibly 2” or 50.8mm).

I spotted this table on the Altair publicity (thanks @StevieDvd). I’m wondering if the FR/FF alone gives 55mm back spacing  and for the ED80 the spacer ring gives 55+8=63mm as listed. So were there other spacer rings available at the time of purchase (6mm for the ED102 and 6.5mm for the ED110)?

1 hour ago, M40 said:

It looks like a TS Optics device, I have a similar 0.8x reducer.

Does the ‘For 80ED’ spacer ring have anything to do with it in your example?

Certainly, the main unit looks very similar, but there are differences in the position of the threads on the telescope side. Lunt seem to include adapters to fit their telescopes with screw threads and provide what looks like a compression ring 2” eyepiece holder. 

I am really seeking clarification about whether the FR/FF could be suitable for use with a WO 110/770 which my astronomy club owns!

I bought this 0.8x Focal Reducer/ Field Flattener second hand in a ‘package deal’ without any specification details. I have searched for an image of one like it on various obvious websites without success so far. From the style and look of it my guess is that it is may be a clone of the units that Telescope Service or TS-Optics used to sell. It has an M42/T/T2 thread on the ‘camera’ end and a tube exactly like a 2” eyepiece at the other end. There is an undercut on this tube also like eyepieces, and scratch evidence that it has been attached at some time to a typical two thumbscrew eyepiece holder like a Sky-Watcher one.

I did find a similar looking one advertised as a Lunt Optics FR/FR here https://agenaastro.com/lunt-solar-0-8x-reducer-field-flattener-with-m42-t-t2-thread-caa-rf.html and I note that this unit is said to be ‘compatible for f7 telescopes from 80mm to 130mm’.

A further item that came in the package deal was an 8mm thick M42/M42 spacer ring as shown with the label ‘For 80ED’.

Anyone care to shed some light on what I have purchased? 

First image of this region I’ve seen so far this year - impressive!

I use the ‘plain vanilla’ Astroberry installation on two RPis simultaneously. I had suffered very occasionally from issues like  KStars 3.5.6 crashing, but much more so when I updated one setup a month ago to 3.5.7, so I went back straight back to 3.5.6 (just copied the old SSD image). Now since Radek announced he had updated his repo to KStars 3.5.8 with INDI 1.9.5 and PHD 2.6.11, I have started running this version and things are going well. I note in Jasem’s Ecosphere blog that there were a lot of bug fixes including for such things as memory leaks.

I have the SkyMax150. The focal length quoted for this scope is 1800mm. In use for planetary astrophotography I attach an ASI533 as closely as possible to the visual back and measure the FL (by platesolving) as longer than 1800mm, so I presume that the specified focal length is that which would be measured (theoretically) at the end of the Maksutov baffle tube, ie certainly not that measured in the practical application with a star diagonal and eyepiece.

Perhaps you would be better off asking for help on the SkySafari community forum directly.

https://support.simulationcurriculum.com/hc/en-us/community/topics/115000039847-SkySafari-Android-Apps

14 hours ago, david_taurus83 said:

Been a while since I used one of these. What was wrong with 3.20? The backlash issue is mechanical problem with the small nylon gears in the little gearbox on the motor. Can't see how software can cure that.

The hope was (and still is) that SW may have refined some other aspects of the 2019 firmware as well as curing the Dec runaway which ‘they had not be able to reproduce’ until last week. I’m not sure if v3.32 is better than v3.20 but in testing it I’m learning a lot about the mechanics of guiding!

Got my fingers crossed! Tonight I tuned my guiding error to a respectable 1 arc seconds so I am happy with v3.32….

@Ags as usual it’s a process of elimination if there appear to be faults in a complex interactive hardware/firmware/software piece of equipment but the AZ-GTi is amazingly capable and does work very well for many (some people are saying it is the presently the best selling Sky-Watcher mount). I have operated mine successfully from the iPad App and via WiFi, although others have reported issues with the WiFi especially in locations where there are many WiFi networks competing for the same frequency spectrum and the AZ-GTi uses the ‘older’ 2.4GHz band only, which is very congested these days. 
The Dec axis runaway issue is a well documented problem in autoguiding in EQ mode with several of the AZ/EQ firmwares Sky-Watcher have offered over the last couple of years. Many of us have had to revert to good old v3.20 from 2019 until two days ago when v3.32 was made available. The Dec axis is the Alt axis in AZ mode, so that does seem to equate to your problem. But if you’re running an ‘old’ AZ-only firmware I haven’t heard of others having your specific issues. 

@Ags Could you let us know which firmware you’re presently running in your AZ-GTi, which mode (AZ or EQ), whether you use an EQDirect cable or WiFi, and what software you’re driving it from (SynScan Pro App, RPi or PC)?
The fact that your change of power supply made an audible difference suggests you may have been running under voltage for much of the mount’s use, and you may well have a corrupted firmware. The intermittent movements you described sounded like typical issues with power supply, but there have been firmware versions which have had issues.

Not squirrels, just the Schlieren effect in play, due to the air currents inside the optical tube which have not reached thermal equilibrium. 

Sounds like your metalwork is not physically earthed by your mains power supply and so is floating wherever the various capacitances take it. I don’t have this with my RPi, but for instance I do have it from time to time with my iPad charger which is connected only to live and neutral with no earth connection. The Apple mains chargers here are two pin types, and they plug in either way round. One way round I feel the iPad metalwork ‘buzz’, the other way round, not.