DSLR Cooling to Near Ambient with Fan Cooler

[Gina]

I'm looking to mount my smaller NEQ3 on the obsy wall for widefield imaging and run that from a laptop in the obsy. I won't always want to shoot widefield of the same subject as the main scope on the NEQ6 and a semi-perm second mount seems better than over loading the main mount and all the balance issues swapping and changing lenses would bring.

One reason for mounting the WF camera(s) on the NEQ6 is that the guidescope and guiding system will work for WF imaging. The total weight should still be well within the NEQ6 limit. At least for a couple of years anyway when I might add an MN190

Hope you're feeling better Gina

Thank you Off to bed shortly - just drinking a hot Lemsip with honey

[Gina]

More coolers - both 50mm 2" so smaller and possibly lighter. Clearly less efficient as there are fewer fins but might be sufficient.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=370529693921

http://www.ebay.co.uk/itm/12-VOLT-0-7-WATT-2-CPU-FAN-COOLER-MASTER-T15-5020C1-BALL-BEARING-UNIVERSAL-50mm-/290639470278?pt=UK_DIY_Material_Electrical_Fittings_MJ&hash=item43ab765ec6

[Chris]

Thanks for the links, I've just bought 2 of the Cooler master low profile CPU fans, I've got a feeling they'll come in very handy in the not too distant future:)

[Gina]

Thanks for the links, I've just bought 2 of the Cooler master low profile CPU fans, I've got a feeling they'll come in very handy in the not too distant future:)

Good - I'll be interested to see how you get on I've ordered a few bits for my dual WF rig this afternoon. Not sure what I'm doing about a second cooler yet. I would have liked the same cooler on both cameras but it probably doesn't matter as long as both work. I don't see any point in changing the one i've done just to have two the same.

[Chris]

Hey Gina:) I'll keep you posted, although it will be on the back burner until I've got my obsy a bit better weather proofed, got a couple of layers of tarpaulin on it at the moment with loose timber joists to hold them up so I don't want the waether to get too bad:( I just need to do finishing touches to the rail system so my RoR can go up, then a bit more damp proofing and felting the fixed roof and a couple of coats of paint plus a roof locking system then I can relax a bit more and start modding my camera:) Finding it dificult to get time on it to be honest, my wife works full time so when I'm not working in the week I'm looking after the baby, so that leaves the weekend and I work a lot at the weekend, its going to be dry this weekend so might get a couple of hours on it after work tomorrow then hopefully all day Sunday:).

I know what you mean about having matching CPU fans, it would be nice for consistancy and aesthetics but ultimately its not as important to have these matching as it is the cameras pixel size and chip size and the same scopes or lenses. Let me guess, you've ordered bits for the dual mounting bar?

[Gina]

Correct! Plus another M42 to EF adapter.

Good luck with your obsy and I hope it keeps fine for you - forecast is not good for here.

[Gina]

I'll try the coolers I've already got for the second camera. Another possibility would be to have an aluminium or copper plate between the two cold fingers and use one cooler for the two but I don't think it would be all that practical.

I've decided to have the WF cameras fixed to the main dovetail and lined up with the scope for the moment. I shall be using a piece of aluminium sheet 200 x 100 x 3mm bolted to the main dovetail and the cameras fixed to that with their tripod bushes and quarter by 3/8 long Allen bolts and washers.

After I've had some experience of the use of this arrangement I may reconsider my options. I may just do either WF or main scope, one thing at a time, or I might look into a separate mount - who knows

[Gina]

Here's a crude diagram of the proposed setup :-

[Gina]

Now working on the second camera. Made the cold finger and dismantling the camera again to fit it.

[Gina]

I've made a slight design change with the second camera to make assembly easier. With the first camera the hole in the back didn't easily clear the cold finger hot end so I've moved the heatsink pad area back a bit by changing the shape of the cold finger bending as shown in this diagram.

[Gina]

Photos :-

[Chris]

he he been busy again then Gina:) you've illustrated your improved design very nicely, good for modding newbs like me to refer to:D I've not long been back from work and tired but it looks like it might be a clear night so its tempting to go out and do the before modding test of my 300D:), just been looking at potential targets with Ha regions, my southern view is orange soup so the Helix is out, considering the North America neb, I'm limited to easy targets as I don't have goto, and I doubt I will see much nebulosity on the 300d screen with my short max 120 second subs, so I might be in the wrong place and not know it, any target suggestions welcome:D

[Gina]

I haven't any suggestions I'm afraid. The best Ha objects I know are out of sight I believe - at least they are for me. M8 and M20 are too low in the west below the trees. And Orion isn't up until later in the night. Probabably the moon will be around then too. I shall be concentreting on the Cygnus Loop but it's rather faint. I shall be using 300s at ISO 3200 at ambient for Ha WF 200mm FL at f5.6 and similar exposure at Dew point +2C on the scope camera for the Cygnus Loop mosaic - weather permitting.

[Gina]

Probably should post the diagram of the insulator that goes between cold finger and pins of image processing chip on the imaging circuit board. This is made of thin hard plastic. I used an offcut of secondary double glazing membrane.

[malc-c]

Gina, I have the answer for you.... kept my old core 2 dual processor cool

Might have a slight weight issue though

[Gina]

Wow! That's a whopper

[malc-c]

Wow! That's a whopper

That's what the misses said

[Chris]

I haven't any suggestions I'm afraid. The best Ha objects I know are out of sight I believe - at least they are for me. M8 and M20 are too low in the west below the trees. And Orion isn't up until later in the night. Probabably the moon will be around then too. I shall be concentreting on the Cygnus Loop but it's rather faint. I shall be using 300s at ISO 3200 at ambient for Ha WF 200mm FL at f5.6 and similar exposure at Dew point +2C on the scope camera for the Cygnus Loop mosaic - weather permitting.

Good luck for tonight:) I decided to do M45 before and after the mod to see if there is any star bloat after, and for the Ha I will do a before and after on M42, I decided to keep things simple for this little experiment. I'm out at the moment doing 20x90seconds at ISO 800, then I'll do 10 darks. My heart sank for a while whilst setting up as my mount woudn't power up but it turned out to be a dodgy connection with the powertank, Phew!!!

Thanks for showing the insulator diagram, although I'm not quite sure I understand? does the insulator slide onto the side of the sensor? bear in mind I've not took a camera to bits yet so not sure whats what yet,

[Gina]

I had a few problems tonight - mainly computer/software. I was getting things in the frame when everything started shifting off at a great rate. Nothing responded so it was a power off job on the netbook. Then having framed my target, PHD locked up and needed killing. After that it all worked and I started on 5m on each system but was getting white clipping on the scope so reduced to 3m. Now the scope camera is taking 3m subs at ISO 3200 and 3C while the WF camera is taking Ha subs of 5m at ISO 3200 and around 10-11C. I've now got over 20 subs of Ha and thinking of changing filters to OIII and grabbing 20 odd of those. Normally I'd grab as many Ha as possible but with the next clear night "who knows when" I think I'll swap to OIII. In a few days I should be able to take both at the same time.

[Gina]

Right... No running 5m OIII subs on the whole Cygnus Loop and continuing 3m colour subs on the Witch's Broom section. Might need to refocus for OIII but I'll see.

[Gina]

Yes, I did need to refocus. So went to Lyra and adjusted the focus thne back to Cygnus. PHD stopped working and I wasn't able to get it going again so I'm taking 90s lights WF OIII and 60s on scope of the Veil. Think I'll pack up soon.

[Gina]

I had a short go in Ha on M42, M43, Running Man, Horsehead and Flame (all in the frame). None too good because of the moon even in Ha - wideband colour was completely swamped. Might get something out of a stack. I was stopped by mist in the end so only managed a handful of Orion area subs.

[fwm891]

Gina, did you try with just a fan and the cold finger i.e. no cpu cooler and fins? Just get the feeling that the fan would be enough on its own!

[Gina]

Gina, did you try with just a fan and the cold finger i.e. no cpu cooler and fins? Just get the feeling that the fan would be enough on its own!

No I didn't. But I will be trying out a rather poor heatsink with fins on the second camera.

[Gina]

There is another possibility - use copper (or aluminium) angle pieces to thermally connect the cold fingers to the mounting plate and hence dovetail and scopes etc.