michael8554

A very well documented project, containing all the fine detail so often missing. Michael

It may not. It will keep trying, but since such large excursions are often caused by backlash or stiction, it may take a long time to correct, unless you have high Aggression. So the star could leave a small guide star box - but perversely too high Aggression could cause overshoots and yoyo-ing. Michael

Your recent unguided Guide Assistant runs show your RA PE heading off towards a peak of 8arcsec and more ? That might explain why the stars "jump" between long exposures. But your guided graphs look great, PHD2 is handling things well. PHD2 doesn't get fooled by large excursions, it will continue chasing them for as long as it takes, and that will show in the GA graphs. Michael

Worrying that you have had to correct the tracking rate. Maybe worth looking at the actual, rather than the quoted PE ? Run the PHD2 Guiding Assistant for 10 minutes and look at the RA curve in the Log Viewer. There are also earlier Mesu posts on SGL that show an uncorrectable by PHD2 fast PE component that gives elongated stars.

Not necessarily East heavy. In which direction do you get movement when you rock the top of the ota ? Michael

I would suggest that perfect balance is not best practise. Even the best mount will have mechanical flex, so balancing heavy in one direction can take up the slack. Also does your mount have zero PE ? Michael

You could ask OVL ? info@opticalvision.co.uk Michael

UPDATE: A user on the LX200 GPS Yahoo forum used the Hi-Link HLK-RM04 WiFi Kit, cost £13 on eBay, took 11 days to deliver from China. Best to put it in a project box, about £5. Also no Tx Rx reverse switch, so pins 2 and 3 on the #507 DB9 need swapping, or you could solder Tx, Rx, and ground wires directly to the WiFi adapter pcb. Login to wifi is 12345678 Browse to the Config setup at 192.168.16.254 Login and password both admin Then in the very first setting "Serial Configuration" change 115300,8,n,1 to 9600,8,n,1 (the baud rate) and Apply. Michael

37.5mm is an awkward figure, so don't forget you can still focus through infinity with a distance less than that, say 35mm. More than 37.5mm won't. Michael

Go back to basics. The 183 has a male M42.5x0.75 thread. The sensor is buried 6.5mm in from the front face. A Canon EF lens has 44mm back focus. So you need 37.5mm of spacers. The FLO device spec is confusing, maybe the 183 back focus is 17.5mm with the black adater fitted (Dave beat me to it) Michael

If you're convinced that tablet and laptop screens don't give even illumination at different angles, then you should try sky flats, or a light box: https://www.ebay.co.uk/itm/A4-Drawing-Light-Board-for-Diamond-Painting-Kits-Tracing-Light-Pad-Box-Table-M6/223224674759?hash=item33f93a39c7:g:CUwAAOSw1cdb5vrm Michael

Stargate Michael

There's a complete WiFi replacement app for the Autostar II handbox available, running on an iPhone or iPad. You don't even need the Autostar II handbox to set up the mount. The app is called ScopeBox and it's on half-price at the moment, £4.99 in the App Store. Review at: http://www.weasner.com/co/Reviews/2017/ScopeBoss/index.html EQUIPMENT: A) You will need a Wifi RS232 Adapter. You can use SkyFi (£245), or Meade Stella (£219), or something like this (£30) - Umm, difficult choice..... I bought this : https://www.ebay.co.uk/itm/WiFi-RS-232-Adapter-Serial-To-WiFi-Converter-External-Dipole-Antenna-WA-232E/192123926853?hash=item2cbb7a7945:g:XOQAAOSwCU1Yv6c~ This company also sells them from the UK, just not at the moment I did this search ! The UK delivery was fast, and they sent me a PDF of the manual when I asked them to, so good service. Appears to be the same as a USConverters WA232. You can also get packages of an uncased module plus antenna plus power supply for about £15 !! 5-27 Volt power source for the Adapter, either mini USB or bare ends. I used a 5V mini USB mains charger. C) Meade #507 data cable. That's the one with a wide 6-pin RJ plug that fits the RS232 socket on the mount, not the #505 with narrower 4-pin plug that is used for updating the LX90/ETX type of Autostar: The DB9 gender needs changing - the #507 has a female DB9, but the RS232 Adapter is female too. So buy a #507 and solder on a Male DB9. This way you can make the cable shorter and mount the Adapter near the mount without cable loops. Or buy a #507 and a "Mini Null Modem Male to Male adapter" : **** I've since discovered that the DCE/DTE reverses TxD and RxD. So switch to DCE with stock #507 cable ***** D) An iPhone or iPad running iOS 6 or higher. SETUP: Set the slide switch on the adapter to DCE(F) Install a virtual COM port on your PC with USR-VCOM utility. Open a browser and go to 192.168.0.3 which is the built-in config pages. Change the Transmit Timer (mS) box to 10 (default is 100) INSTALLATION: 1) The WiFi Adapter should have the DCE/DTE switch in the DTE position. **** in DCE position, see above **** 2) Plug the WiFi Adapter into the left RS232 port on the mount. 3) Switch on the WiFi Adapter and connect to its WiFi signal with your iPhone. No need to enter any settings in iPhone. 4) Switch on the mount. 5) Open ScopeBoss on your iPhone. 6) Go to the "Connect" screen, and enter first time settings of IP: 192.168.0.3 and Port: 5000 7) Press "Connect to Scope". The screen should go back to the keyboard display, with the text window showing your usual start-up message ("Daylight Saving" in my case, with the mount GPS turned off). Simples ! Michael

This project has taken so long I'd forgotten why I started it...... I wanted to mod a 6D and preserve Autofocus, an expensive camera so worth doing once it's open. And a good selling point if I ever resell it, daytime shots are usually okay with a Custom White Balance. But have I used up all my enthusiasm? Watch this space ! Michael

I have now modded a Canon with Floating Sensor adjusted by Torx Screws, a T3i aka 600D. I found it well worth while taking the front off, so that the top could be slid up to give better access to the Torx screw to the left of the viewfinder, and to the topmost ribbon. It's 3 screws on the bottom, 2 screws at the front under the "Canon" sign, and the diopter adjustment for the viewfinder. Then ease the front over the tripod boss and remove, there are no cables. The top panel will then ease upwards, still attached by some cables. I missed the holes in the ribbon cables that allow you to pull them in and out with a toothpick, only a couple on this model. I found the LPF-2 filter to be 0.60mm thick, not the 0.50mm I had found in my research. Read my very first post with this in mind. This means the adjustment to preserve Autofocus is 0.21mm. Or tighten 5 more Torx "Points", after returning to the factory setting. This is much closer to the "half a turn" that Croz's contact suggested for the 600D. I had rejected this as too far, based on my 0.50mm thick filter calculations. Tests after reassembly showed that 5 Points was not enough. The Autofocus point was closer to the camera than the target. So I opened her up again and moved to 6 Points, or half a turn - Croz's figure. This figure gave correct Autofocus !! So much for all the maths I had applied to this problem ;-< However it does give a figure that can be applied to other cameras that may have different LPF-2 filter thickness. If 0.60mm Thickness = 6 Points Then apply 1 Point per 0.10mm of Filter Thickness. Over and Out. Michael

As Ken said, lacking feedback from the mount about where it's pointing, putting the approximate Dec into PHD2 will enable it to tweak the RA corrections you obtained at zero Dec for any Dec you use. Michael

The autofocus midpoint on my Canon 18-135mm lens is nearer to the camera than the target, before and after modding. Ive read an unconfirmed suggestion that this is a deliberate move by Canon. The point and click user focuses on the target and expects everthing in front to be in focus too, not bothered about the background. Are your lenses like this or was mine made on Friday? EDIT: The User Guide says: "In the Basic Zone modes, the camera will normally focus THE CLOSEST SUBJECT" - (my caps) But my test were done in the Creative Zone on the rotary dial...... Michael

Today I modded a Rebel XSi (or 450D) The sensor sits on 3 sets of shims, this one had: Top Left 0.47 (0.35 + 0.08 + 0.04) mm Bottom Left 0.39 (0.35 + 0.04) mm Right 0.47 (0.35 + 0.08 + 0.04) mm YOURS MAY BE DIFFERENT !! The 450D LPF-2 was 0.65mm thick, as on all previous modded 450D's. The correction for correct autofocus for that thickness of filter is 0.23mm So I needed shims 0.47 - 0.23 = 0.24mm and 0.39 - 0.23 = 0.16mm I made new shims from feeler gauge material, two 0.20mm, and two 0.08mm, and reused two of the 0.04mm shims 0.24 = 0.20 + 0.04mm and 0.16 = 2x 0,08mm Your homemade shims will need two holes in, one for the screw and one to fit on one of the locating posts. That's because it would be very difficult to get the tiny shims under the sensor plate and aligned with the screw holes. Also you can't just make one hole and place the shim over one of the posts, because the bases of the location posts that the shims fit on are lower than the post the screws go in. Here are Before and After shots showing Depth of Field, 135mm lens wide open. You can see that the Autofocus range on this Canon 18-135mm lens is not perfectly centred on the inclined ruler on the Before shot. But it is out by about the same amount in the After shot. In both shots the barcode target is inside the Autofocus range. That IMO has proved the calculations used to correct Autofocus, next task is a 600D and those pesky Torx screws !! ***** EDIT: after all these fancy tests I have neglected to try the obvious one - focus on a distant object. Autofocus was spot on, but manual focus through the viewfinder gave out of focus images. The focal point was closer to the camera, like the close-up tests below, but unfortunately the distant object was not in the depth of field window. The LiveView focused shot of the distant object was of course in focus. I will have to investigate what's going on here.... ****** ****** EDIT 2: Based on the 600D Floating Sensor mod I did next, the 450D sensor could be usefully moved closer to the shutter by using even thinner shims. The correction figure for the 600D turned out to be 0.25mm for a 0.60mm thick LPF-2. So for the 0.65mm thick 450D filter the shims need to be reduced by 0.65/0.60 x 0.25 = 0.27mm ****** Michael

Hi all Here's a quote from page 1 of the mods: "Comment by Oz: "Use a fine tip sharpie and draw a line on each of the ribbon cables where the ribbon exits the connector before disconnecting the cable. This will give positive visual feedback when reconnecting the cables to assure they are fully seated and square before locking the connector tabs." Thanks for the diagram Croz. For those of you puzzling over the diagram, the white "sticks" 1, 2, and 3, are a representation of sticks placed onto the sensor bed behind the Torx screws, with the screw height marked on them. If you've also radially marked the head of the Torx screws and the chassis with a Sharpie, the sticks will probably get you close enough, the final adjustment being to match up the Sharpie marks. Now I see this is marked as a "Baader Modification" To me this means the LPF-2 being replaced with a Baader BCF filter. I haven't discovered the thickness of the BCF. Or whether it does preserve Autofocus, but Gary obviously feels it doesn't and gives it a small 1/12 turn tweak. This is not the same as only taking out the LPF-2, you need 4/12 for this mod Gary also says to tweak 1/12 turn for the "Full Spectrum + Astronomik MC Clear Glass". So a retained LPF-1 and a Baader BCF are the same thickness as both filters removed and replaced with clear glass ? Hmmmm ..... Michael

Hi Croz You've been very unlucky, I've never had to re-open a camera after modding to reseat ribbons, did you mark where the ribbon enters the socket with a Sharpie like Gary suggests, so that they go back in straight and to the right depth? Yes the Sharpie marks on the screwheads and chassis are crucial if you want to avoid sensor tilt, you need to be within half a point of the mark. How did you end up thinking of moving 5/12ths in? Is that what you calculated from your filter thickness measurement? It's good though that you've confirmed one calculation for me, in part D of my last post I thought that half a turn was too much and would leave the autofocus point too close to the camera. Could you send me the link to Gary's guide with depths of 1.95mm for 2 left screws and 1.75mm for right? Interesting your Torx were T6, were they still 0.5mm pitch? Michael

Tolerances for the Torx Adjustment Four ways of looking at it: A) In Gary Honis's shim adjustment for a 450D Full Spectrum plus Astronomik Clear replacement: http://dslrmodifications.com/rebelmod450d6a.html He found the basic spacer to be 0.35mm, and sensor tilt was adjusted by an extra 0.10 shim on one post, and an extra 0.05 shim on another post. So don't expect the 600D screw heights to be the same, sounds like each sensor's tilt is adjusted during manufacture. The smallest shim 0.03mm equates to 0.72 points. Which suggests if you get your adjustments accurate to about half a point you should be okay. Canon's tolerance for the lens mount to sensor distance is +/- 0.02mm, or +/- 0.48 points - there's that half a point tolerance again ! So getting the 600D back to the factory setting by aligning the Sharpie marks (after setting the height as close as possible with your digital micrometer or marked piece of cardboard) should be straightforward. C) Now my calculated correction for the 600D, if the LPF-2 is 0.5mm thick, is 4.08 points. 4 points is easy, but how many mm are those extra 0.08 points ? It's 0.0033mm, or about a 1/10 of the tolerance, so setting to 4 points in should be good enough. D) Croz's contact said "half a turn inwards". Taken literally that's about 2 points more than calculated, which is 0.083 mm more. IMO this is too far in to work. Michael

Well why didn't you speak to him weeks ago and save me all that effort? Joking, I have enjoyed the challenge and your confirmation is the icing on the cake. Please let us know how you get on with returning the sensor to the factory position, and the thickness of the 600D LPF2, and how many extra points you screwed in. Good luck Michael

The aim is to restore Autofocus, and focus to infinity. The Canon lenses I have tried on an unmodded 450D all go through infinity focus, so some latitude is built in, but the expensive "white" lenses may be more finicky. Even wide open, perfect autofocus is depth of field symmetrical to the subject, which can be measured with the classic method described on the internet: an inclined ruler next to a target, the out of focus points on the ruler should be the same distance behind and in front of the target. Ideally the mod should mimic that, but some offset would still be acceptable, so long as the target is in focus ? Hmm.... Canon spec the distance from the lens mount to the image plane as 44.0 +/- 0.02mm. For earlier non-floating cameras such as the 450D, there are 11 adjustment shims available, ranging in size from 0.03mm to 0.35mm. I will be using cut-up feeler gauge material to correct the 450D I will be modding next. The calculated correction figure depends on the value of RI used, but the results using 1.517 (Gary Honis) and 1.545 (Schott) only vary by about 0.01mm, so fall within Canon's tolerance. I checked a modded/autofocus not corrected 450D on a scope with offsets smaller and larger than the calculated correction figure, the results suggest that the calculated figure for the 450D of 0.23mm/0.22mm is acceptable. For floating sensor models such as the 600D, the next problem is how many extra points to screw in the Torx screws ? All that depends on is the pitch of the Torx screws, which Croz has helped confirm is 0.5mm. You need a good quality Torx screwdriver, an Allen key is not the same and could damage the screw. Comment posted to the Gary Honis site: "I tried two different T7 drivers, and could not get a bite on the screws. I used a T6, and that worked fine. Canon could be using different sizes." Well Croz has also confirmed they are T7, however a cheap T7 screwdriver with a misshapen tip might well be a poor fit. Getting there Michael

Wow, well done Croz !! The thread certainly looks very coarse. Now the convention is that "M1.7 x 5.5" SHOULD mean a 1.7mm diameter screw with a 5.5mm pitch, which this clearly isn't, so 5.5 is probably the length. The screw in the image has a shoulder under the head, but without that I reckon there would be 11 turns in 5.5mm, or 0.5mm pitch. That's very pleasing to know. Michael