Oddsocks

Looking at the side-by-side image you posted, all the donuts in the master flat have concentric bright rings around them. I thought at first that this might be just a bit of jpeg-ery edge detection enhancement going on with the screen capture but the fact you see these artefacts in the calibrated light suggests it is a real artefact in the flats.

Posted screen captures are really much too low quality here on the SGL forum to make an accurate diagnosis and it is always a good idea to post the fits images as well, or a link to a Dropbox or Google Drive folder containing them when asking for help with image artefact or calibration issues.

Taking your screen capture and applying curves in PS shows that the darker donuts in the flat master are also present in the calibrated lights, it is not just the bright arc that remains after calibration. 

There are only two ways to produce bright concentric ring artefacts in the flat masters (using PI) that I am familiar with.

First is a change in focus during the time it took to take the flats, i.e, the telescope focus was not consistent across the full sequence of flats used to create the master.

Second, either bias frames were not taken and included in the batch processing script (or if using the manual calibration tool in PI, a bias master was included but the tick box 'calibrate' was not ticked in flats selection window), or there is a temperature mismatch between the lights, darks, flats and bias frames, and/or a matching dark frame for the flats was not included in the batch processing script.

Because both the bright ring and the dark donuts are present in the calibrated image then it confirms the flat is not calibrated correctly.

In PI when calibrating images from a 8300 sensor it is essential that the full set of matching temperature calibration frames are included, if the flats exposure is longer than a few seconds, then matching time and temperature darks are also recommended.

If it is simple case that you did not take bias frames, or matching time dark frames for the flats, set the camera to the same temperature as for the lights and take a series of bias frames and matching time flat-dark frames now and rerun the batch processing script with the bias and flat-darks included, that should fix the bright ring artefacts around the dark donuts in the flats and calibrate the lights correctly, if it doesn't, try the manual calibration tool instead as I find it often produces better results than the batch processing tool as you have more control over the fine-tuning characteristics of the calibration procedure.

If you did take bias frames and flat-darks and include them in the batch processing script or manual calibration tool check the fits headers for the bias, darks, flats and lights, were they all taken at the same temperature? If these images were taken with the G2-8300 the 8300 chip shows a great variation in dark current with temperature so it is important the temperature is consistent across all the frames used (as I found out with my own QSI 683 that uses the same sensor).

I can't offer a post processing solution to fix your current image but maybe going back over the calibration procedure with the full set of matching calibration frames will solve the problem and you won't need to resort to "air-brushing" the final image.

HTH.

22 hours ago, Shahd said:

I processed the data from last night, and it worked! thanks a lot

You are welcome Shahd, I'm happy I was able to suggest a possible answer to the problem and that you did't waste time retaking the luminance and calibration frames unnecessarily. 

17 hours ago, ollypenrice said:

Every day's a school day when you read an Oddsocks post! Much appreciated here.

Thank you for the kind comments Olly.

When diagnostic imaging (medical) was my career I found the professionals I used to support appreciated an explanation for the problems they might be seeing with their equipment rather than just a blanket response that told them nothing as some of my colleagues tended to do.

Some of my bosses over the years used to complain that I never sent e-mails, only novella! 

I do try to include as much as I can in as few words as possible but as you know it isn't easy!

13 hours ago, wimvb said:

If there was such a thing as a best post challenge, this would be the winner.

You are too kind Wim, I do appreciate your comments and trying not to blush. 

The post was written in rather a hurry and looking back now I would have changed the sentence structure and shortened it a bit to make it easier to read, there's always room for improvement!

William.

Whenever you see ‘Bas Relief’ effects (3D) in subtracted or divided images this is almost always due to mechanical movement between the two source images, in this case the images are the flat master, or flat stack and the target image stack.

DBE has detected and enhanced the image artefacts resulting from mechanical differences beween the master flat and image stack. The dark areas around the galaxies is most likely due to poor placement of the sample points in DBE/ABE

Most likely there was some physical movement of the L filter, camera, flattener, focuser etc, either during the flats acquisition or the lights acquisition and this may have affected the entire series of flats, or lights, or just a few individual subs in either stack.

Since you report that RGB were ok but only L was affected I would suspect the filter wheel maybe was knocked during the sequence, possibly the L filter is loose in its holder or the wheel detent is a bit loose in the L postion allowing some movement as the telescope assumes different positions for flats and target imaging, or possibly the flattener to filter wheel coupling is a little loose, even slight focuser movement can cause these effects.

The artefacts are quite large making me think these are dust particles further up the image chain than the filters. You can measure the donuts in the image and determine how far from the sensor the dust particles are and that will give you a better idea of what moved, filter or coupling between filter wheel and flattener, focuser, OTA etc using the formula:

D=Pdf

Where D= the distance from the sensor to the dust casting the shadow, P=The width of the dust donut in pixels, d=The width of a single pixel and f=The focal ratio of the telescope. If you use the pixel size in millimetres then the distance will be in millimetres too, if you use pixel size in microns the distance will be in microns so you just need to be able to convert accordingly. Once you have the distance calculated you can work out what moved.

HTH.

Check the following two images for a possible answer to your problem.

Screen shots are from Photoshop CS6 on a Mac.

This is how to enable/disable automatic hands free execution of an Action:

First image, in the Actions list there is a selectable button to the left of the Action name, this is called the Dialogue button, when this button is selected and 'lit' then the Action will proceed step by step and pause where it requires you to interact in some way followed by an ‘OK’ to continue.  (*See footnote below*)

To run an Action without manual interaction select the Action title and not the Dialogue button to the left of its name, if you do accidentally toggle the Dialogue button so it is lit just toggle it again. The box must be dark for the action to run ‘Hands Free'.

Second image shows the Actions menu.

Click the menu icon at the top right of the Actions tab to open the Actions Menu.

Click 'Playback' options.

Choose 'Accelerated'... for fastest automatic execution or choose, 'Step-by-Step'... to watch each individual step in an action execute, optionally, define a fixed pause time for each step by selecting 'Pause For'.

For each of these Playback options as long as the dialogue button to the left of the Action title is not lit then the Action sequence will run automatically without user interaction and will follow these option choices. If the dialogue button to the left of the Action title is lit then none of these options will have any effect and the Action sequence will proceed Step-by-Step requiring each step to be acknowledged with an ok.

H.T.H.

*Note: Some Actions do require user input to achieve the best results since they are optimised for a particular 'starting state' of the image, which your image may not meet. Unlike some dedicated astronomy image processing programs Photoshop does not evaluate an image to determine image characteristics and adjust processing parameters to suit the image, you need to manually adjust tool settings used for some Action steps to suit your image. 

To see which steps in an Action normally require user input first toggle the Dialogue button to 'on' (lit) then expand the Action by clicking on the right-arrow immediately to the left of the Action title and scroll down the list of Action steps. Any individual Action step that has the Dialogue button 'lit' would normally be a point where you need to make an adjustment to a setting so that you get the best out of that step.

If you wish, you can choose individual steps in an Action to not require user interaction while leaving other steps that do by disabling the Dialogue button associated with that individual step. When you do this the Dialogue button next to the Action title will change to include a short horizontal bar in the centre of the box, this is notifying you that something has been changed from the way the original Action was created. To restore the Action to the way it was originally written click on the Dialogue button immediately to the left of the Action name and the bar through the centre of the Dialogue button will disappear indicating that the Action has been returned to it's original configuration. 

If you decide to run an Action fully hands free, with the Dialogue button next to the Action title deselected (dark) then you almost certainly will not get the best results from the action. An action should really be thought of as a set of regularised procedures rather than as automatic image processing.*

On 13/03/2018 at 12:29, Rattler said:

When you say convert to 16 bit do you mean in 'Mode' and then selecting 16 bit?

Yes, convert to 16bit using Mode before anything else.

When you select an action is the dialogue button to the left of the Action name selected and lit?

If the button is 'lit' then the Action will pause at each step in the action sequence and prompt you for an ok, at least this is my experience running Astronomy Tools Action set in Photoshop CS6 for Mac.

To run an action automatically just click on an Action title while making sure the dialogue button to the left of the title remains dark, if it is 'lit' click on it to toggle it off then press the 'play' button at the bottom of the Actions tab.

See following post for pictures and explanations.

Were these working at one time for you and have now changed behaviour?

I don’t know about Annie’s actions but Astronomy Tools action set only works properly with 8 or 16 bit images, I’ve been caught out a few times importing 32bit images and trying unsucessfully to run actions on them. If you import a 32bit image you have to convert it to 16bit mode before attempting to run actions.

One other issue I have noticed several times is that if you open an individual action and toggle the tick boxes for any step in an action a warning message will appear saying what you are about to do may not be reversable, continue, Yes / No?, or words to that effect, if you go ahead and toggle the step then sure enough the action will stop at that point and wait for you to respond to an ok prompt however going back to that step and toggling the selection box back to how it was does not reset the action, it will always stop at the same point again and wait for you to ok. The only way I have found to fix this is to delete the entire action set and reinstall it.

I am not a PHD user and don't know the software that well but there is interesting information in the log window, statistics box shows RA RMS was 97.19 pixels against DEC RMS of 1.79 pixels, graph shows clearly periodic error but the scale is too large in the posted image to be able to see the guiding corrections and Luke reports the stars are trailed in the RA direction. To me that suggests that PHD is locked to the guide star but no guiding corrections are being issued to the mount. Luke's PA is good so no drift in DEC but no mount corrections would cause star deformation in RA direction due to PE and gradual drift over time in RA due to mount tolerances/ belt mod/wrong RA rate set, etc etc.

To fault find further and as already noted above I think you would need to set up normally take a series with guiding enabled and then immediately after another series with guiding disabled. If there is no difference between the two series that would indicate that for some reason PHD guiding corrections are not being issued to the mount even though PHD is locked to the guide star.

Other than that you could go into ASCOM diagnostics and enable logging then read the log after a guiding session to see if guiding corrections are being sent to the mount (assuming you are using ASCOM guiding of some kind).

The PHD guiding log can be read like a normal text file and it may show the guide star's centroid position throughout the run, if the x and y centroid position is the same at the end of the run as it was at the beginning but the main camera image is drifting then that would indicate either flexure, rotation, or the guide camera image is not being updated.

Depending which capture software you use in some software packages you can configure storage of the guide camera images along with the main camera images, a quick comparison of the start and end run images from both cameras would confirm flexure or rotation, if the guide camera images show no drift but the main camera does then = flexure or rotation, if drift is seen in both guide camera and main camera images then guide corrections are not being sent to the mount.

How far off axis is the guide telescope compared to the main telescope? is the guide star selected in the same frame as the main camera? A big differential and a little polar misalignment would create drift due to rotation.

There are two possibilities that I can think of:

1: Capacitively trapped electrons in the rows and columns closest to the left side and bottom edge of the array where there are, depending on the particular deign of detector, a number of "dark" rows and columns used for on-chip dark calibration, these are covered by a vapour deposition metal plate a few atoms thick and the plate could, in theory, form one pole of a capacitor.

2: Beyond the dark rows and columns are the row and column amplifiers that are a source of IR. The amount of IR emitted is a constant since the read time of the row and column amplifiers (and therefore their "on" time) never varies irrespective of individual exposure time and would be a source of low level read noise added to every exposure. The IR, depending on source intensity, can only penetrate so far into the wafer.

Without knowing the actual structure of the detector, which would be a design secret, it is not possible to say which of the above is the most likely, the irregular shape of the "glow" hints at a capacitive trapped electron theory but depending on the layout of the row and column amplifiers the leaked IR from the row and column amplifiers is just as likely.

One test you could do is to flood the detector with light and read the array with a single exposure and then immediately cover the detector and take a dark bias, if the edge glow changes after the flood exposure then that would hint at the trapped electrons explanation since flooding the detector will dislodge some of them, if the edge glow is exactly the same after the flood exposure then that would hint at IR from the row and column amplifiers as being the source.

You might find the linked document of interest:

https://courses.cs.washington.edu/courses/cse467/08au/pdfs/lectures/07-cmos-ccd-imagers.pdf

On 19/12/2016 at 14:40, Merkhet said:

Thank  you.

The original  battery is still in the handset from when I bought it new in 2000, almost  seventeen years  ago and still working.

You are more than welcome, makes a change for a question to be asked that I know a little about.

I would change the battery as soon as possible and not risk leaving it until it stops working, this design of battery was never meant for the consumer market and has special characteristics that make it difficult to handle.

The electrolyte is highly reactive with water and although the battery case is stainless steel the case seals are known to deteriorate over time and once they fail and water vapour contained in normal air enters the battery a violent reaction occurs that causes the case to swell up and split, the contents are highly corrosive (lithium salt) and often the battery will split, leak its contents over the circuit board they are attached to and within a few hours the board will be destroyed.

Although very rare for a genuine traceable battery from a good manufacturer, I have known these batteries to suffer seal failure, swell and split, less than a month after fitting.

Ten years is about the maximum predicted mechanical life once the battery is installed and in use.

Lithium Thionyl Chloride is highly toxic as well and has to be disposed of as hazardous material.

When you change the battery take care not to short it out while removing the old one and fitting the new one, although they are low current batteries and can only provide approx 30 to 40 mA this is sufficient to cause the battery to explode if the short remains for long enough.

You can find further information about the chemistry of this battery at the following Wikipedia page and looking down the list for the chemical formula LI-SOCl2  (IEC Code: E)

https://en.wikipedia.org/wiki/Lithium_battery#Chemistries

The battery type ER6V/3.6V is an industry standard "AA" Lithium Thionyl Chloride data backup battery and it is not rechargeable.

There are rechargeable Lithium batterys but these use a different chemical composition and construction technology, known as Lithium Ion, they have a high internal leakage current and are unsuitable for data backup since they need recharging every few months, they also may have a different terminal voltage to the type fitted to your handset, typically 3.7V to 3.85V

Your handset will only work correctly with the standard, non-rechargeable ER6V/3.6V "AA" Lithium Thionyl Chloride battery and the most common makes are Toshiba, Saft, Varta and Tadiran with power ratings of around 2000mAh to 2600mAh, these should last around ten years in storage and five to eight years in use, depending on storage temperature and equipment use, the longer the handset is powered up and in use the longer before the backup battery needs replacing. Toshiba sold their battery business quite a few years ago and I don't know where the Toshiba branded batteries are coming from now.

Be careful where you buy the battery from, there are a lot of counterfeit fakes around, especially on internet auction sites, the counterfeits are known to leak, catch fire or explode, if in doubt it is better to pay a higher price to buy one from a trustworthy supplier.

I used to fit the Varta made ER6 AA type to medical systems here in the UK and we bought ours from RS because of the guaranteed supply chain, you have to check the solder tab orientation and layout though. Some solder tab batteries have a right angle, large, single tab at one end of the battery and a right angle, small, double tab at the other, some have axial tabs, some have axial solder leads or opposing tabs etc but all the variants should have the standard "AA" battery style body, ~50mm long and ~14.8mm diameter.

RS stock all the typical solder tab types, about twenty five variants last time I looked, you just need to search for 3.6V AA lithium non-rechargeable and you should find them all, linked below are the most common types I last used, any of the types linked below with the correct solder tab arrangement will be suitable.

http://uk.rs-online.com/web/p/aa-batteries/7020815/

http://uk.rs-online.com/web/p/aa-batteries/7781153/

http://uk.rs-online.com/web/p/aa-batteries/7781150/

http://uk.rs-online.com/web/p/aa-batteries/6684553/

http://uk.rs-online.com/web/p/aa-batteries/7020818/

HTH.

55 minutes ago, PhotoGav said:

I hope the dome is now fully functional after your travels and you are enjoying the upgrade from the SkyPod.

Thanks Gav.

Had a great summer travelling and on the last few days staying with the partners in laws in Switzerland, supposed to be out sailing today but tipping down so just reading eating and drinking today!

Will be home this weekend and then the fun starts getting to grips with ACP and setting up the Paramount MX sky model PEC and polar alignment, reckon that will take me a month (at least).

58 minutes ago, old_eyes said:

Oddsocks; your point about not touching the walls is well made and a good warning. I like your separate block idea.

Best of luck with your dome old_eyes.

Only other tip I can give re a concrete pad if you go that way is to make sure the surface is properly sealed before the dome is installed otherwise the sealant they use around the base will not stick, I was lucky that the builders were watching out for me while away and they found lots of water inside the dome one morning after the sealant had peeled away from the dusty concrete pad, the builders lifted the dome in one piece and sealed the concrete with Ronseal Concrete Sealant, which is a solvent based acrylic polymer that penetrates deeply into the concrete slab and dries in a few hours, then they lowered the observatory back onto the pad and redid the silicone rubber sealant, that was back in May and since then it has remained dry.

On 04/10/2016 at 09:49, old_eyes said:

could I ask how you supply power to the dome? I want to have a mini-consumer unit in the dome and I was wondering how to place/fix it to the curving wall.

Having worked with industrial high voltage power supplies in medical systems, up to 200 kV, in often damp operating theatre environments I'm all too aware of the dangers of dampness and electricity!

I did my own installation but not being domestic qualified I still had to have it certified by council building control.

Power out to the dome was by buried armoured two core, live and neutral only, with a two metre earth rod at the dome and the cable armour grounded at the house supply end only, insulated at the dome end. All dome earthing is via the grounding rod including the steel pier. Consumer unit, light, light switch and sockets all IP66 waterproof rated, consumer unit and sockets all individually RCD protected, overkill really but I already had the RCD protected sockets for another cancelled job.

The Pulsar dome has an inward fitting dome-wall flange so it is just possible for some rain water drips to be blown inside the dome as well as condensation drips from the dome roof to track down the to the dome-wall flange so it is not a good idea to mount a consumer unit directly on the wall as any drips from the flange may fall on it.

My Pulsar dome has a single bay and if you have a bay you could fix the consumer unit inside the bay on the flat wall, but I wanted my bay free for computer and networking so I mounted my consumer unit, three double sockets, twin network ports and earth distribution box all on a piece of varnished 3/4 ply 1 mtr tall and around 300mm wide. The plywood panel is screwed to a block of wood on the floor set 60mm away from the wall, there is a stand-off wood block screwed to the dome wall flange-web three quarters of the height of the wall.

Difficult to visualize but imagine a free standing plank set away from the wall and screwed to a wood block on the the floor with a single wood block supporting the plank near the top. This means no screw holes in the dome exterior wall just a single bolt hole internally where each wall segment meets its neighbour and forms an internal webing joint.

By standing a panel inside the dome any dripping water from the dome-wall flange falls to the ground behind the panel and being a flat surface the consumer unit and sockets are simple to fit.

The panel was transferred from my old Skyshed POD and attached are a couple of pictures from when it was installed there, the only change being the stand-off support is nearer the top of the panel in the Pulsar and in the Skyshed the stand-off is fixed to one of the POD wall through bolts, in the Pulsar it is fixed directly to the turned-in wall web where the individual wall panels meet.

The pictures were taken before the network cables were terminated so are just seen looping out of the surface mount box, in the Pulsar these are now neatly terminated.

17 hours ago, old_eyes said:

Would it not be better to mount the dome on a wooden decking platform? Is there any reason why this is a bad idea?

I had Pulsar dome installed this Spring on a concrete base, the Observatory has not been used through the Summer due to travelling but is being commissioned now so no real data yet on thermal cooldown rates but if you look at professional observatories of the last few hundred years they are built on concrete or brick and not on decking! 

The key is good ventillation. There were some condensation problems initially with my Pulsar dome and builders carrying out restoration work on my home while I was away fitted a solar powered stainless-steel ships yacht's extractor fan in the southern wall, this runs all day and contains a small rechargeable battery that keeps the fan running for an hour after sundown. 

On an observing night the shutter and entry door would be opened at the onset of twilight and imaging or observing won't begin for at least another hour and this should be sufficient to allow most thermals to diminish to a negligible level.

During the day the vast mass of concrete, base and pier block, are shaded from direct sun being inside the observatory so the concrete mass will be closer to average ambient then say a concrete path or roadway that would sit in full sun all day. Once the observatory is open and the pad begins to cool the rate of heat transfer would be quite low, concrete is not a great thermal conductor and with a low transfer rate thermals set up inside the observatory should not really be that great.

Last couple of points regarding a concrete base, you won't be leaving the floor inside the observatory plain concrete, not a good idea, expensive gear does get dropped and it wont bounce on concrete! Most have some kind of floor covering and the interlocking 10mm thick foam rubber tiles that many use both insulate the floor against thermal transfer from concrete pad to inside dome as well as providing excellent protection against damage to falling items. If you do go for a concrete base then if possible design it to be no bigger than 150mm wider than the dome to keep the unshaded concrete to a minimum and also to minimise the area that standing water can accumulate, good drainage is essential all round the dome to prevent water creeping under the dome walls. I made my concrete pad octagonal being a bit lazy and not wanting to spend ages on the shuttering for the concrete pour but I think the the bases made with circular shuttering look really neat and meet the requirement of minimum exposed concrete to sun and standing water

Regarding decking I can be more certain since my previous Skyshed Pod was on decking and it was a continual problem with water leaks, rotting timbers, insect infestation as well as the occasional rat or mouse problem.

Decking really is meant for sitting on in removable chairs etc, it does not like things left on top of it as water will collect under said objects and in no time begin to rot the decking.

With decking, the timbers expand and contract a huge ammount with the seasons, properly installed, a gap of several millimeters is left between each decking plank and it's neigbour to allow for seasonal expansion, this gap is a good route for water to track below the dome walls and start to rot the timber within a few months of fitting. Decking timbers are probably the cheapest low grade "flooring" you can get, it is certainly not allowed for internal house construction, cut from the tree heartwood after all the good stuff is removed for other purposes it often has tightly radiused end grain which means the planks warp width-ways and continually move as the moisture content changes through the year. Any extenal silicone sealant used to seal the observatory base to the timber decking is continually pulled away from the joint by this timber movement so you will be chasing leaks. Inside the observatory the gaps between the planks allow free movement of creepy-crawlies as well as high water vapour movement from the ground below and the space below the decking is a great place for a rats nest. Any timbers that do warp or rot badly will need the observatory jacking up so that the plank can be extracted and replaced which means the entire observatory timber-dome seal has to be cut away and redone.

If you try to install a water barrier sheet above the decking and below any internal dome flooring this just allows the decking timbers to become sodden with condensed vapour from the ground and if you place the barrier sheet between the decking beams and planks this just does the same to the beams, seems you just can't win.

There is no doubt that a small dome looks good on decking but as a practical proposition I found it a continual headache and given my experience decking would not even be a serious proposition.

HTH.

William.

1 hour ago, stoffe said:

Is it possible that gain should be at that low value that I have in my settings?

Yes, that value is quite plausible.

In the first document I linked to: ( http://www.astropixel.gr/uploads/7/8/3/5/7835053/scientifically_determining_ccd_gain_and_offset.pdf ) the authors tested their QHY9M and determined their gain as 17% with an offset of 112 so your current settings of 19% and 110 are not that far away but remember these numbers though very small have a big effect on the way the camera records the image and to get the best out of the camera you need to measure and set the gain and offset accurately.

41 minutes ago, stoffe said:

I guess I can not copy the settings from a another QHY9 owner directly then.

 

You can copy from someone else but the offset and gain values they use will only apply to your camera if the factory QA was observed exactly for each camera assembled and that there has been no calibration drift caused by ageing components in your camera since it left the factory.

This document explains the steps to take, bit lengthy but easy to follow:

http://www.astropixel.gr/uploads/7/8/3/5/7835053/scientifically_determining_ccd_gain_and_offset.pdf

Also a Craig Stark blog which is a general description of the offset and gain functions:

http://www.stark-labs.com/help/blog/files/GainAndOffset.php

William.

Hard to tell from your sketch but if the loop at the top is hinged then the only common screw type like this is used for fixing cameras to tripods and is called a "D RING SCREW" and is commonly available in one thread size, 1/4", but different lengths.

Here is a long thread version at Amazon:

http://www.amazon.co.uk/Yosoo-Mounting-Adapter-Flathead-Stainless/dp/B012CLIF24/ref=sr_1_18?s=diy&ie=UTF8&qid=1454840107&sr=1-18&keywords=d+ring+with+screws

If you go to ebay uk and type D RING SCREW in the search box you will find several listings in different lengths.

I thought I had all that covered a few months ago, that precise distance, CCD etc...  I bought some spacers (little plastic rings of different thickness).

Either I got it majorly wrong, or the focuser tube has to go out quite a lot.

The W.O. M72 would normally be used visually with a diagonal.

For imaging, with the diagonal removed, and the camera positioned directly in the beam path you have to add a distance spacer of at least 50mm between focuser draw tube and the flattener because the M72 does not have a huge focuser movement range to compensate for the diagonal not being there.

You can run Regim on iMac OSX I've just tried it on mine but it is not at all easy or user friendly.

Firstly Regim runs on the JAVA platform and Apple disabled JAVA on OSX earlier this year because of a security issue.

JAVA has now been updated to address the security problem so firstly you need to go to the JAVA website and download OSX compatible JAVA version 7 update 40 and install it.

Then download the Regim software for MAC OSX, the zipped files should automatically unzip to the MAC download folder.

Now the really silly part, you can only run Regim from inside a terminal window, there is no other way to do this, a few hints for using a terminal window in MAC OSX can be found here:

http://mac.tutsplus.com/tutorials/terminal/40-terminal-tips-and-tricks-you-never-thought-you-needed/

The instructions for how to run Regim from the terminal window can be found in the Regim english instruction manual here:

http://www.andreasroerig.de/regim/regim_e.htm

Starting a program with command line instructions is like going back to BASIC or DOS, can't believe this software has been written this way?

I use several stacking and processing software packages on my iMAC but I run them using Parallels desk top running Windows Vista (would have preferred XP but this was all I had a license for).

We MAC users are rather poorly provided for in the astro freeware/shareware market at the moment so either Bootcamp for a full dual boot Windows installation or Parallels for a virtual Windows installation were the only option for me, Parallels needs a lot more RAM memory to run a virtual Windows alongside the MAC OS seamlessly, Bootcamp makes less demands.

Best of luck anyway, hope the above is of use.

Hi Gina,

I remembered you tried fine wire without success, how about a set of feeler gauges?

You might then be able to apply extra heat to the feeler gauge directly as you poke it under the sensor cover without adding extra heat stress directly to the detector.

William.

RS (UK) carry a large range of suitable tapes but you do need to set up an account to buy on line and postage charges etc add quite a bit to small order costs.

Maplin also carry an inexpensive 0.9mm thick tape that can be used but it is not as thick as the original Telrad tape which is around 2mm thick.

So to get good adhesion over a large area and mould to the shape of the OTA you need to double it, stick two layers together and it works fine.

http://www.maplin.co...foam-tape-33766

William.

For cover glass removal this technique might be worth a try.

Glue the end of a piece of flat metal bar around 200mm long and of a cross section shape that is the same size (for cold removal), or slightly smaller than the cover glass window (for hot removal) using super glue.

The glued metal surface needs to be as flat as possible so that it bonds to the glass window with the same surface tension across the entire area.

Now when you try to prise off the glass window either cold or hot you can apply a little sideways force to the bar at the same time lifting the edge of the window.

This should spread the stresses across the entire window and help prevent it from shattering.

If all goes well and the window comes off in one piece then place the metal bar and glass window in a close-able glass container and add a solution of acetone (in the open air...not indoors!!!!) for several hours to dissolve the super glue, the two pieces can then be separated with a thin scalpel or hobby blade.

I used this technique a few times for removing radiation protection lead-glass (Pb) port windows from obsolete medical X-ray sources so that the X-ray source housings could be reused.

(Pb glass in X-ray sources is very thick ~1cm but extremely soft and fragile, you couldn't handle it with normal tools, it would crumble away but the glued-to-a-bar method worked a treat)

Gina, have you tried finishing and polishing the faulty sensors and then washing with a mild solvent and rinse with distilled water, sounds crazy but you only need a microscopic piece of dislodged conductive silicone to be embedded in a sensitive area of the wafer and this may be causing the temperature related errors, because the gold wires are not very springy if they were damaged you would expect them to be permanently broken and not make/break with temperature change but the wafer surface is much more easily disrupted and a tiny piece of silicone bridging two conductors could easily make/break with temperature.

Whatever the outcome this has been a great thread to follow, much better than anything on TV, has anyone approached you yet for the film and book rights?

William.