MAK 127 and ZWO

[brrttpaul]

I have decided to get the mak and a colour zwo for planetary but how do i go about fitting it to a MAK is it just a case of taking the diagonal off and screwing the camera on or will it need spacers? also I found a 2x barlow lens the other day so took it out to the obsy but I just cant figure out where it goes, at the moment I have the telescope (ed80), the flattener, the filter wheel and the camera (think i also have a spaer on there ) so where would a barlow go? im just curious for the ed 80 but I presume it will be easier to fit on the mak with a colour cam

[Cosmic Geoff]

I have a 127mm Mak which I have used for planetary imaging as follows: leave the diagonal in place (for convenience, just remember to flip the image appropriately during processing). Put ADC in the diagonal. Put 25mm eyepiece in ADC, get rough focus, lift eyepiece by 6mm, rough focus again. Drop ZWO ASI120 camera  into ADC and connect to laptop, check aim with 6x30 finder.  Hopefully the desired object will show up in the full field, somewhat out of focus, if you have enough exposure.  Adjust the focus. Definitely no spacers needed, just knob twiddling.

For best results, slew to a star and fine focus, then slew back to the desired object.  Fine adjust the exposure (using histogram). Reduce the field size to speed up the frame rate. 

With a refractor you can probably pencil mark the focuser barrel with the approximate focus point for the camera. I have not had much joy using a Barlow  but have seen online guides on Cloudynights (I think) suggesting how to attach Barlow, colour wheel etc in suitable order.

I hope this helps.

[brrttpaul]

that is a great help thx, as I understand it the diags that come with it are not the best. reason i asked about the barlows is on astreobin all the better pics seem to be taken with a barlow

[Cosmic Geoff]

3 hours ago, brrttpaul said:

reason i asked about the barlows is on astreobin all the better pics seem to be taken with a barlow

True. The Barlow doubles the image scale, but whether that always improves things is another matter. Experienced imagers may care to comment. 

[catburglar]

There’s a fairly straightforward way to determine if you may need a barlow for any given scope and camera combination.

The optimum focal ratio for planetary imaging is somewhere between 3.56-5.36 x pixel size in microns.

For the ZWO 120 and 224 cameras with 3.75micron pixels you should aim for a focal ratio of around 13-20.

For the 290 series with 2.9 micron pixels aim for F10-15

For the 178 series with 2.4 micron pixels aim for F8-13.

I wouldn’t stray much beyond the upper threshold because that just reduces the signal to noise ratio, although you can recover this by stacking more frames in post processing.

I think your mak is F12, so you probably need a 1.5-2x Barlow for the 120 cameras and probably don’t need one for the 290 and 178 series.

Edited May 19, 2018 by catburglar

[brrttpaul]

Cheers guys great help

[mr saddo]

Hi, I've just bought on if these zwo 120..had a go on jupiter last night, cold! Clear,  I could not get image on screen  using sharp cap,  it was just a round light properly the front correcter plate on the  mak 127  tried inward outward focus, I focused on a 10mm e.p then put the camera in to the diagonal, does the diagnal need to be off, with the camera up the back of scope, or in a barlow in the diagnal, spent 2 hours nothing, gave up, very annoyed. Scope skywatchher 127mak. 

[Cosmic Geoff]

1 hour ago, mr saddo said:

Hi, I've just bought on if these zwo 120..had a go on jupiter last night, cold! Clear,  I could not get image on screen  using sharp cap,  it was just a round light properly the front correcter plate on the  mak 127  tried inward outward focus, I focused on a 10mm e.p then put the camera in to the diagonal, does the diagnal need to be off, with the camera up the back of scope, or in a barlow in the diagnal, spent 2 hours nothing, gave up, very annoyed. Scope skywatchher 127mak. 

Been there, had that experience. Read my earlier post.  You will not get anything unless the camera is almost in focus.

Edited November 21, 2022 by Cosmic Geoff

[mr saddo]

Read the above Ile  give it another go when clearer!  

Edited November 21, 2022 by mr saddo

[Carbon Brush]

If you set a fast shutter on the camera and try in daylight, that makes it much easier (and warmer) to check out focus capability and FOV.
Given that you may be looking at a nearby TV aerial, roof, etc you don't need a clear sky.

HTH, David.

[mr saddo]

Hi I can get it to work during day...but on scope takes me forever to get anything on the lap top screen, camera seems to lock up when you start messing with the sliders in the menu seems a delay, weather the cold his affecting it I don't know. I did get  jupiter but it disappeared screen went black. Gave up spent 2 hours no footage, gave up.