Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.



  • Content Count

  • Joined

  • Last visited

Community Reputation

1,396 Excellent

About david_taurus83

  • Rank
    Brown Dwarf

Profile Information

  • Location
    Birmingham South
  1. Are you referring to the apparent inability to control offset? In the drop down box that says unity gain is also the option to select custom. Once selected, the offset slider becomes available. AFAIR anyway
  2. Which features are you talking about? Originally I wanted the Atik mainly because of the UK customer service and the reputation they have for quality but I was swayed by the cheaper ZWO which comes with all the adapters you need. Rarely hear about issues with the ASI1600 anyway. I assume your aware of the microlensing issue of this sensor which will affect both Atik and ZWO versions.
  3. More like Astro Tax to me! I'm that tight I use those cheap solderless connectors and make my own cable!
  4. 19 quid for a cable?! What's wrong with these?
  5. Done some more tests last night. I tilted the camera on the left side as initially thought but it didnt appear to make much difference while checking focus again in APT. So I tilted the right hand side and went to about 0.6mm. After taking a few subs it looked a bit better. Not perfect star shapes but they look smaller. I only managed 22 x 120s subs on M27 but they present a nice image for such short integration. This is the full frame with no cropping at all. And the inspection version: Star shapes are still slightly pointy on the edge but perhaps I'm asking for too much with the full frame 6D. I usually crop out edge artifacts and the bottom mirror shadow anyway. From experience they look smaller in the subs where previously I was used to seeing good focus and tight stars in the centre with larger stars towards the edge. I cropped the image down to show how this scope would perform with APSC sized chip and as expected, very good results. For reference, here is an unprocessed image of M101 with slightly enlarged stars on the edges. I cant decide if I've made much of an improvement?!
  6. I've yet to see good reviews about DFO.. Mainly complaints about people not getting their mount back for months. Anyway, I can vouch for the CEM25. Cracking little mount. I can pick mount and tripod (no counterweight or scope obviously) up with one hand. Very accurate gotos and the guiding is as good as it was with my heavy duty AZEQ6. Fragile? I wouldn't say so. Mine actually fell off the tripod when I undone the locking clamp and it's fine despite damaging the GPS module! I would say that if you were to lock down the RA axis and pick the mount up and ram the counterweight bar into a doorway then yeah, you might damage the worm gear. Its spring loaded and designed to slip up the main gear if theres excessive load so if you locked it down with no play in the spring it may cause damage to the brass worm. I usually leave my scope attached and transport the rig to and from the garden carefully but I ALWAYS remove the counterweight and bar before doing so and always have one hand under the mount. It would also manage your 130PDS BTW.
  7. For a while now I've long suspected that either my 6D has some sensor tilt or its a combination of this plus the addition of various adapters and perhaps focuser sag. There are too many variables to pinpoint exactly the problem! I first noticed the issue on my Altair Starwave 70 EDQ-R flatfield quad (same as WO Star 71) where the left hand and centre stars look good but the right hand side stars looked out of focus. Even on my 'normal' 102mm ED doublet with flattener, it also appears that one side of the image has better correction and star shapes than the other, with the only thing common with both setups is the Canon 6D and the camera rotator/tilt adapter/filter cell holder I use between both scopes for a secure threaded connection. Last night I spent a few hours taking some measurements with the quad refractor. As it has the corrector lens fixed in the OTA, simply focusing with my auto focuser and recording the steps taken should give me an idea of the correct spacing needed across the 6D sensor. Both scopes have the same R&P dual speed focuser, exactly the same as the WO and TS versions. A while ago I physically measured the steps sizes and I calculated that 450 steps with my DSD AF3 focuser is equal to 1mm. My backlash is 0.05mm so 23 steps. I started in the home position with mount tracking and camera in the upright or horizontal position. To rule out any issue with the focuser causing the tilt or a collimation error I also took sets of measurements with the camera rotated 90 degrees with the sensor in the vertical position and also took measurements pointed both east and west. I used the auto focus aid in APT and picked a star on the left, centre and right hand side of the image and ran the focus routine. To rule out any inconsistancy with APT repeated this 2 or 3 times on a different star in each zone. Results as follows: Scope in home position, camera horizontal. Left side best focus : 752 (step number) Centre best focus : 735 Right side best focus : 680 The lower the step size is to focus IN and the higher the steps is to focus OUT. So assuming we want best focus in the centre and to extend out across the sensor, the left side needed to focus out so the left is too CLOSE. The opposite is said of the right, the step size is lower and I needed to focus in so it is too FAR and by a bigger margin than the left. Overall left to right for the above the max difference is 72 steps so 0.16mm of tilt. Scope in home position, camera vertical Left side best focus : 798 Centre best focus : 755 Right side best focus : 645 Left to right 153 steps, 0.34mm tilt Scope pointed NE at 45°, camera horizontal Left side best focus : 765 Centre best focus : 705 Right side best focus : 631 Left to right 134 steps, 0.29mm tilt Scope pointed NE at 45°, camera vertical Left side best focus : 738 Centre best focus : 668 Right side best focus : 620 Left to right 118 steps, 0.26mm tilt Scope pointed W at 32°, camera horizontal Left side best focus : 715 Centre best focus : 675 Right best focus : 616 Left to right 99 steps, 0.22mm tilt Scope pointed W at 32°, camera vertical Left best focus : 775 Centre best focus : 650 Right best focus : 624 Left to right 151 steps, 0.33mm tilt Apart from the first sample and the relationship between left and centre in the last, the results all appear to correlate. There are variables to consider, the 23 steps backlash, possible focuser sag. I noticed in NINA when autofocus is running the V curve is more of a U curve so there does appear to be a generous amount of steps in the critical focus zone either side of perfect. These factors may obviously impact the above test but all samples above show that the left side appears too close and the right side too far away in relation to the centre. An average of 121 steps and 0.27mm tilt from left to right. So the left side needs to be moved outward away from the corrector while leaving the right side as is. What I'm not sure about though is which side to of the tilt adapter do I adjust? Do I open the left side by approx 0.27mm as if you were to view from behind the camera? Or does the camera auto flip left to right due to how a lens works?! Any thoughts on my conclusions?
  8. Yeah I just found that website. JC wept at the price though! Tenner for 16mm long bolt!
  9. 8mm diameter. Here's caliper set to 1mm. Looks too big to me! And then at 0.75mm.
  10. I'll have a quick look again. Yes, with a digital caliper. It may be 1mm pitch as I can find those on Ebay
  11. The dynamic range is still 12 bit, that doesnt change. The driver only scales the ADU value to readout in 16 bit mode. So if you have a star centre fully saturated at 4095 ADU in 12 bit, the driver just scales the value up to 65535 ADU in 16 bit. The brightness stays the same, it doesnt change. Only the readout value! That's my understanding anyway!
  12. I have trouble balancing my CEM25. Much more difficult than a SW to balance! Needed to add some weight to the end of the dovetail to balance the dec. Impromptu but it worked! This video explains better about balancing off centre. https://youtu.be/X8w77MrpB3o
  13. As above, can anyone point me in the right direction? I want to replace the tightening screws on my Altair focusers and camera rotator with cap head bolts so I can use an allen key to tighten or undo them as they are very difficult to access with all the kit I have mounted on the scopes. I ordered some M8 cap heads off Ebay thinking the pitch would be the same but obviously not! I can easily find M8 x 1.25 pitch but I need M8 x 0.75 by the looks.
  14. Its 12 bit but the driver scales it up to 16 bit so as far as PI is concerned its 16 bit.
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.