Adam J

There might be something very slight there but to be honest if it is that then its not a twist its a defect / dint in the vane...not sure if skywatcher would do anything about that after 9 months of ownership...

Mine was almost entirely towards the rear end of the scope on the current screws even without changing the current screws I just moved if forward about 6mm. Might that explain something? What was it that prompted you to do it?

I am assuming that i do that by winding in the adjustment screws....if i go too far will the primary fall off? I dont want that to happen lol

Thats why I tried to place the center of the secondary mount in the center of the primary so that in theory the vane would appear to vary in width if twisted. Or at least that was my theory. What i need is a short flat surface to lay on top of the vane so that I can see if it is flat against its entire length.

Yes but not quite as pronounced....i see it on several DLSR pictures in this thread so it makes me suspect that the cause may be the ingress of the focus tube due to the DSLR back focus I cant find an example on a CCD image.

I have a little play but it looks ok to me here are some pictures for you guys to look over. I added a straight line to show that they are straight. Let me know what you guys think. The thing that confuses me is that the unwanted spikes are much dimmer. The focus tube is in the same position i locked it off in for focus with the M45 picture. It looks to me like it may be clipping the very edge of the optical path. Am actually looking at it now wondering if the secondary is slightly rotated anti-clockwise....

Ok here is a good question, assuming it is a twist that I have missed, what is a good way to test for it? I am basically eyeing it up against a steal ruler and cant see anything. Is there a better method? To help me out, given that it is the vertical spike in the image that is doubled and that the camera was mounted with the long axis of the sensor parallel with the OTA, am I correct in thinking that with the focuser pointing straight down as I look at it will be the horizontal pair of vanes that I need to be looking at?

I would agree with this. I just dither to remove dust and hot pixels from the image and even out the color noise takes about 16 frames to be effective. I do use a chunk of Bias frames normally about 24, but as I cooled my DSLR to -10c in my M45 at 300s bias is actually the bigger noise component not thermal.

How much twist are we talking about here? I cant see any at all...so unless we are talking fractions is a mil differenct from each end then I am not sure. Its a DSLR so the focuser is almost fully retracted into the tube and is within the light path. Ill pist a picture of the vanes later tonigt.

I am not sure but I think you are trying to say that the weight attached to the skin of the scope may be causing flex in the tube wall close to the secondary mounting points making them flex? Problem is that they look straight with everything attached and I am already mounting my finder guider over the rear tube ring. But ill have a look and see.

Just boosted the blue channel a little. I am going to try and get another 75 frames over the next few weeks.

Tried to correct the Halos.

I am still getting extra diffraction spikes despite checking for the spider veins being twisted (they are not). Could it be the focus tube in the light path? I am also getting purple halos on the stars (see below) my camera has an IR filter and the only glass in the system is the MPCC MK3. Could the CLS clip filter be causing this? Some sort of reflection? Actually looking at it the direction of the extra spike is not the same in all the stars....collimation...tilt? Btw 24 x 300s 130pds HEQ5 pro

Yes nose. you need to use a c-mount nose piece extender.

Ok, so I decided the best way to look at the sensitivity at a given wavelengths was just to use my 2 inch H-a and OIII filters to create a pair of flat frames and compare pixel values on the Bebrayered section to the edge with both micro lens and filters still intact. I have summerised my finding in the table below. The real shocker for me was that the OIII seemed to increase in sensitivity where as the H-a decreased in sensitivity on a per sub pixel basis. Honestly not sure what this means in terms of real world imaging....i suspect it means that ill have to increase the lenght of my H-a subs but that noise will be greatly reduced leading to a lower total integration time???? The totals for each 4 sub pixel group are significantly higher, however as I noted before I am not sure how this will translate to the real world, i am reasonably sure its not the same as having the equivalent increase from a single pixel though. Btw I have no idea why the luminance reported by Pix Insight is higher than the 4 sub pixel average... Sorry if this is becoming something of a monologue lol.

Cheers, Ill have a look at DCRAW I have never used it to be honest. Could you be more specific on the advantages of this method? See below for my analysis of the effects of sensitivity for the 1000D.

If I look at the sum lum of all channels in Pix Insight LE then I am getting a very slight reduction for green, a slight increase for red and a big increase for blue.....I am not totally convinced that this mod is going to help sensitivity a hug amount as things stand in may have a positive effect on signal to noise however. I am not sure how the quantum efficiency of OIII, H-a and SII is effected by the transmission at those wavelength of the bayer matrix alone....it is possible that at those specific wavelength rather than the broader bands in my test the RGB matrix may also be less than 100% transmission. If this is the case its possible that some performance will be gained at these wavelengths. Finally I would say that despite my best efforts the test colors are not pure and as such this may result in the performance of the mono area of the sensor being overs estimated. Although the area I selected around the edge for comparison looks clean, there is no grantee that the micro lens is completely undamaged. Could anyone comment? The three shots below are RED GREEN AND BLUE (in that order) flats shot with the camera in mono (b/w) mode. The brightness variation is likely the variation inherent in the color balance of my monitor.

Your contributions to the thread where very valuable in helping me get a good result. I am going to make a video on you tube of the process as I think my chosen method was quite effective for this sensor anyway. I just need to find another 1000D at a reasonable price or I may try a 450D. I have done a little analysis of the results: 1) I set a custom white balance in the camera to balance out the contribution of each of the red green and blue channels....not sure if this is the correct method. Should I be doing this? 2) I used my PC monitor to make some individual separate Red Green and Blue flat frames. So MS Paint custom Color and 0, 0, 255....etc. 3) I then used PixInsight LE to take a look at the average pixel readings for the area center area incomparison to a clean section of the border (with the filters and micro lenses still in place) ???Should I be setting the camera to Black and White mode??? Looking at just the pixels of the relevant color in both areas of the image I found that the lack of micro lenses reduced sensitivity as follows: Red: With Filters and Lenses = 0.669 , Removed = 0.479 (71.5% of original value) Green: With Filters and Lenses = 0.843, Removed = 0.662 (78.5% of original value) Blue: With Filters and Lenses = 0.651, Removed = 0.524 (80.4% of original value) So for each sub pixel type there has been a reduction in sensitivity of between 20% and 30% due to the micro lenses being removed. At least if my methodology is sound. Clearly from the attached picture the green is brighter then the red and blue on average....not sure if this is due to double the number of green pixels or due to double the number of green pixels on the monitor or a bit of both. But this does make sense.... This is when my knowledge runs out and I could use a little help. How should I be processing this? Clearly when I use my H-a filter I am going to now get 4 x active sub pixels instead of 1 x active sub pixel. However, each sub pixel will only be ~70% as effective due to the removal of the micro lens. So......the bit I dont get it this, I suspect that 4 x sub pixels together to not equal one single pixel with 4 times the collecting area. Am I gaining 4 times the sensitivity or am I just effectively getting an average value of the 4 sub pixels, similar to stacking 4 frames? Should I be converting to gray scale in processing? I am a little confused. Or by doing this am I only effectively gaining resolution at the expense of some sensitivity???????????? Some help would be appreciated.

In all seriousness I am looking for another sensor as I think that I can get it perfectly flat without scratches on my second attempt so if you dont get around to it and want to sell it then I would be happy to buy it from you. I used "Meguiars Plast.Rx" Polish. White plastic bottle with a black cap with a pointed felt polishing tool for a Dremil but by hand only. I did not mess with the wires with epoxy, or even attempt to get close to the blue area around the edge of the active sensor region. From reading the entire thread I think that 95% of the problems have arisen from trying to get too close and using the wrong type of epoxy on the gold wires. If you dont have patience and a steady hand I would save yourself some money and not bother lol. I am a perfectionist and so it hurts not to do the whole sensor but I have just told myself that I am going to have to crop it out of the final image. Good Luck.

Cleaned and cropped flat frame, not too shabby if you ask me. Its a testament to the work you guys have done on here that i can get this result from my first attempt. Comes out at 7.2 mega pixels after cropping the rubbish out. Edited to add a picture of my scope and DSLR cooler taken with the mono 1000D.

Hey all, would like to show you my first test photo from my debayered Canon 1000D, having read this thread I opted not to even try to push to the edges of the sensor, ill happily crop it. I removed the tougher micro lenses first using a cocktail stick and then the filters themselves using car plastic polish. This is a practice sensor and I will be doing another 1000D soon taking into account my experience. One scratch just to the left of the penguins foot caused by me pressing to hard, did not know how hard i needed to press on at first and way over did it. Everything else baring the edge is dust or loose bits of the filter layer that will vanish with a little more cleaning. Over all nothing that wont disappear with a little dithering and some flats. Clearly focus is not perfect due to the filter having being removed. P.S I know that many people say that you can remove the cover glass on the 1000D without heating but I found that this was much easier when taken to a mild 60c using a hair dryer.

How are people dealing with secondary mirror dew on the 130P-DS, I have been using a hair dryer but to be honest its not ideal as a intermittent solution when the thing dews up half way through a 20 min sub and you lose it. I have been thinking about glueing a 400ohme / meter nichrome wire onto the back of the secondary. But I am shocked to say that I cant find much in the way of advice on this online... Any advice from my fellow 130P-DS users would be appreciated.

It will be fine for SW150PDS to not bother with the replacement filter. I use a 130PDS with a coma corrector and no replacement filter and its totally fine. I dont have a ED80 but my gut feeling is it would be fine too so long as you dont try to use a focal reducer with it. But ultimately just try it an see what happens. If you do get star bloat it wont be horrendous like it would be with no filter at all.

It can stop the star bloat but like i say its a little less aggressive than the Baader so it lets a little more IR through. Canon filter = 750nm cut off vs Baader filter = 690nm cut off. ED Doublets tend to not be optimized for chromatic aberration beyond 700nm so although its better than nothing its still letting 50nm more IR get past to the sensor than would be optimal. It would mean that the optical system would be less tolerant to adding a reducer / flattner for example. It would probably also depend on just how fussy you are about minor star defects too.

Ok I understand it can get confusing. So ill try to condense this into the following advice. 1) Take out the filter nearest to the sensor and leave the other filter in place (the one with the wires attached). This will give you a massive boost to nebula. Do not replace it with a baader filter for now you probably dont need it. 2) If you experience any issues with star bloat / strong colored halos around stars, then buy the Astronomic CLS CCD clip filter. It would need to be the CCD version to stop the star bloat as only the CCD version has the IR cut. That will get rid of the bloat. The only difference between the CLS CLIP and CLS CCD CLIP filters is the IR Blocking Filter. However, it will depend on his optics as to if he needs the additional IR blocking filter or not which is included in the CLS CCD. If he does not get star bloat with his setup then adding the LP filter becomes a completely separate concern. However, if he did get star bloat it has to be the CCD. Either way as these are external filters he can just try it and if he needs one without having to open up the camera again. Finally I seem to remember that the CLIP versions of the CLS filter have an additional anti-reflective coating in comparison to the 2" and 1.25" versions. But I may be wrong about that.