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.

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?

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!

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

Its 12 bit but the driver scales it up to 16 bit so as far as PI is concerned its 16 bit.

Theres a video for installing an Astronomik XL clip filter for full frame Canon. It looks like the filter itself holds the mirror in place afterwards. I wonder if the same principle would apply to all DSLR bodies if you were to use a small rectangular frame positioned under the mirror like an accurately 3D printed part?

https://youtu.be/7As7VkK5rtg

My 600D was a lot noisier than my current 6D. Still, it doesnt appear to affect any images with my setup due to vibrations. I wonder if there is a way to physically keep the mirror in the up position. I know some XL clip filters for full frame require the mirror permanently up but not sure if it's the actual filter that keeps it in this position.

Focal length input of 60mm is likely the problem with a 12.89 arc second pixel scale.

Edit: ^ What Michael says!

Just now, m.tweedy said:

Just ordered one for my travel rig i am setting up

 

Just make sure you have a 5.5 x 2.5 barrel plug for the 12v input. I think hes done it this way so as not to get them mixed up. All the outlets are the standard 2.1 plugs

To echo what Gina has already said, a bit of foam lagging around the camera body will help keep the casing cooler. How are you controlling the tec module?

2 minutes ago, Juicy6 said:

Not a good plan. You will have correct voltage at full amperage but way too many volts when only low consumption is drawn. You need to use thicker cables!

Its 13.5 when cooler switches off so no fear of going over but I understand your point.

1 minute ago, Juicy6 said:

15 m cables - you need to look at this:

Voltage drop calculator

 

Christer, Sweden

Yes I'm dropping around 4v after adding a coolbox for my camera and total draw of 6amps. I prob need 2.5mm cable (currently 1.5mm) but looking for something that stays flexible. My current cigar socket thingy has a voltmeter. So 16v output from PSU and I have 11.9 at the mount!

31 minutes ago, Fellside said:

Hi

I have been using one of these for a couple of years now. I fitted a couple of brackets on the back to allow for a more secure fitting on the mount. It has five outputs plus a powered USB, three outputs are switched, all are fused, LED indication. Mine cost just over £12.00. They seem to be out of stock at the moment, maybe Chinese production problems. A model shop some ware may have one.

https://hobbyking.com/en_us/hobbyking-powerstrip-fuse-protected-power-distribution-board.html?queryID=f652c9d2778130497b5237eefc3bda50&objectID=38455&indexName=hbk_live_magento_en_us_products

Yes £400-£500 is a lot of money to spend. I rarely uses the switches on my Powerstrip and very never have to cycle the USB on and off. I have a SharpSky Pro that runs my focuser and dew strips.

I did own a Powerbox for a couple of months then sold it on. I shouldn't have justified the cost to my self🙂

Anyway £12.00 well spent, great value.

Graham

 

I really like the look of these. I have a triple cigar socket type thing between mount and PSU but I'd much rather something like this and banana plugs. I'd probably just add a voltmeter/ammeter before this to monitor supply at mount end 15m from PSU.

Or if your looking for something simple which is 12v in (5.5 x 2.5 barrel plug) and 5 no. 12v out ( standard 5.5 x 2.1 barrel plug) and 2 no. USB 5v out. Its tiny as well!

https://deepskydad.com/dchub2

I'd say Arcturus is too bright. It's ok for a b mask maybe. The thinner the lines though makes it easier to centre them so a very bright star might bloat the middle out. If using the HFR approach with focus aid it's better to loop short frames and try and take an average reading. Also, turn off the screen stretch in APT if using focus aid as you can see the effects of focusing better.

Yes been dithering every frame with a settle time of about a minute. Its 10 minute subs so cant complain. When I shot my flats they had come down to 3 or 4° again. I had a quick look at a couple of subs in Pixinsight. On the left is non cooled from a couple of weeks ago, on the right is from last night. Not exactly a scientific comparison but the right hand ones look a bit better to me. Or is it wishful thinking?!

New HEQ5 with belts? You should have an almost perfect L shape on calibration.

21 minutes ago, Robindonne said:

The fl is 418 mm.  Do uou mean i just take a rule and measure the distance from the lens to the camera?    I think im in short of length to have some margin but how do i get these extra mm’s the best?

Yes it should give you an idea of where you need to be.

What is the focal length of your scope? You could measure from where the objective is down the scope to where your camera sensor needs to be. Should give you an idea of spacers if needed. I have done this with my 102EDR. With both 1.0 flat and 0.8 reducer, the length is still approximately 710mm.

Cracking image!

-8° tonight. I've set it to that so potentially it can go lower. It's about 10° ambient. EXIF temps showing 5° but I've never known this to be 13° above ambient so wondering if it's actually lower. Not doing darks anyway as dithering. I would say this project is a success. Much better than I was hoping for.

What camera have you got? 1GB will fill up quickly.

That's really excellent! I'm renaming this object though to The Skyrim Nebula

What's your budget? I got one of these in the Amazon sales and it's been great. It's set to login without password and load VNC at startup. I can control it then from my phone. Haven't used a laptop since.

If it's on this site then asks the moderators to "have a word". If the seller doesnt come to their senses then name and shame so nobody else gets the same treatment?