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So I routinely have issues with guiding. Last night, I was getting some solid sub exposures of 5 minutes on the Flaming Star Nebula. When it got to about 15-20minutes of the meridian, I began getting trails on my stars. Then after the flip, I was still getting trails despite PHD reporting all's well. I moved over to the Horsehead Nebula and tried 5 minutes there, and it behaved itself. Then I tested it on the Jellyfish Nebula and it also behaved (just about - minor trails). But it just did not want to dig it with the Flaming Star Nebula, which was practically near the zenith (about 2:30am 30/11/19).
I tried recalibrating PHD (I use Pulseguide so the scope knew where it was). I then also recalibrated PHD at Alnitak so it was near the celestial equator (as the PHD best practices recommend). I even checked my Polar Alignment (done with a Polemaster), which was fine. I couldn't find anything wrong.
The guide scope was slightly off alignment with the main OTA, but that wasn't making any differences before the Meridian.
I did find the helical focuser of the Starwave 50mm guide scope I was using to have some movement in it again when I manipulated the guide camera. So that's something I need to look into. But before I start throwing money at this issue, I see the terms "flexure" and "differential flexure" coming up. Can anyone shed light on what this means please?
I tried manipulating the OTA in its tube rings, that didn't yield any movement either. The piggyback scope is secure, the g/scope is secure in its rings as well, there's no movement in the OTA focus rack and the cameras are secure in their tubes.
I do have my guide rings quite far back on the body of the telescope to assist with fitting the guide scope piggyback.
Video of g/scope play:
Flaming Star Nebula. 5 minute sub, post Meridian Flip, about 2:50am (30/11/19). Note the plate solve compass in the top left. Drift appears to be in S/W direction.
Position of tube rings (they're now at the focus end).
I think I am leaning towards needing to move my tube rings (once I remember to get the tools from work).
(brand new) Skywatcher EQ6-R Pro, SW Evostar Pro 80ED, Altair 0.8x R/F, Canon 600D, Altair Starwave 50mm Guide Scope, Altair AR130 Mono Guide Cam.
By John Lawley
Hi - I've not posted here before as only just launched into this hobby, although I've always been massively interested in astronomy.
I had first light on my rig last night, which is:
Esprit 100, HEQ 5 Pro, ZWO EAF, ZWO mini filter wheel, skywatcher 50ED guidscope with ASI120, ZWO1600mm Pro, Lynx dew controller w 2 astro zap tapes
A big endeavour to get that lot working from zero experience, but I love a challenge and have really enjoyed the computer side (I'm a grade A nerd)...
So - what went well... I got the guide scope in focus (was stressing about this), and also the main scope. Even more awesomely, the autofocus routine in SGP is working perfectly Filter wheel also working perfectly and I'm getting lovely smooth pics from the main camera (I've already done the flats and darks while I was waiting for clouds to clear). Final good thing (well, good-ish), is that I got the platesolving working eventually, and was able to get the scope to align from Park to the Soul Nebula and centre fine. For some reason the "number of attempts" in my SGP profile hadn't applied, so it was giving up after 1 go, but I got it working in the end.
So the bad...
I couldn't take any data because every time it finished the platesolving and started PHD2, PHD2 would start the calibration process and then halfway through, the sidereel tracking on the EQMOD panel would turn off. Obviously, that would lead to a "lost the star" error. Is there some reason why sidereel tracking would turn off like that? I'm generally a bit confused as to whether I should be controlling the telescope from SGP (i.e. unpark) or using the park and unpark + tracking button on the EQMOD panel. Both PHD 2 and SGP are setup to use EQMOD ASCOM HEQ5/6?
So at the moment I can't do anything, because there's no way of guiding without it turning tracking off
Also I was cold. Very Very Cold.
From AST Optics selling my mini guiding system that i used for my Redcat51 , i have used it also with my Esprit 100 and had excellent guiding results.
There is a nice review here if someone wants to read :
Lens: f=100mm F3.5 CCTV objective - made in Japan
Adjustment: by ballhead - with reliable clamping
Dovetail: compatible with most finder shoes
True field of view: 2.9° x 3.8°
Maximum guidable focal length: 1000 mm
Focusing: via lens cell
Connection to camera: C-Mount
Lens filter thread: M30.5mm P=0.5
Weight: 79 grams
Length of the objective: 44 mm
PRICE : £100 (selling the mount and the CCTV lens not the camera)
Paypal accepted buyer pays the fees
I will cover the postage expenses
Ok, so this is a really annoying bug / problem that I have with my setup:
From time to time, in non regular intervals the image my guiding cam (ZWO ASI120) send seems to get flipped / mirrored or looks like it's from a completely different patch of sky.
When I'm paying attention to the guide images I can clearly see that the image seems to be flipped in some way.
It only happens for 1 frame PHD send a warning ( No star found / Star lost Mass changed) and after that everything is fine again. My gear is all connected to a single USB3 Hub which then runs via powered USB3 cable to my Pc.
I'm not binning and have the noise reduction off (though PHD might got hickups while processing) but it still happens. Sometimes there are minutes between two events sometimes it happens 5 times in a row.
It also seems like it's only happening during guiding, I haven't seen it happen during calibration yet...
I'm completely clueless what's happening or how to get rid of it, any help / idea is greatly appreciated.
I have an EQ5 telescope mount which i use for astrophotography. I have modified it with a motorised RA axis using a bipolar stepper motor - my thread for the build is here .
I want to expand the mount's tracking ability by motorising the DEC axis and using a guide scope/camera. I generally use the mount in fairly remote locations so would like to use a raspberry Pi for portability.
I understand that I'll need to use a Raspberry Pi Camera Module for the guide camera.
The capability I want is:
1. guide the mount along RA and DEC axes using a guide star as feedback
2. track the mount using the RA axis only, and if possible continuously take 20-30 second exposures on the guide camera (this functionality is optional, but would assist in polar alignment of the mount)
I don't want any GOTO capability. I am very new to RPi and need some help:
- do I need to write code for this, or is there existing programming available for what I want to do?
- is it possible to avoid the use of screens (in the field)? My preferred option would be to flick a switch to start and stop the guiding, with another switch for alignment mode (or something simple like this).
- do I need to use any particular stepper motors/drivers for raspberry Pi? I'm using a bipolar stepper motor running quarter steps, with an A4988 stepper driver
- is the RPi 3 Model B+ the unit I should buy?