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recommend me a 1.5x 1.25" barlow for planetary

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#1 iwols

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Posted 22 September 2022 - 11:02 AM

using a 2.5x powermate which ive been told is too much for my c8 edge with asi462 camera can anyone recommend me a 1.5x 1.25" barlow for planetary



#2 BGazing

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Posted 22 September 2022 - 11:12 AM

using a 2.5x powermate which ive been told is too much for my c8 edge with asi462 camera can anyone recommend me a 1.5x 1.25" barlow for planetary

Yes ,you need 5x pixel size, so 1.45 or thereabout. 7x in great seeing...

You can try custom Siebert barlow.

I got myself a Baader VIP barlow (for solar and planetary on small refractor), it is modular and you can adjust the spacing and magnification as you wish.

Asi 462 has 12.5 mm depth to sensor, 5mm will go to the 1.25mm nose, so 7.5mm. Screwing VIP Barlow nose and two 15mm spacers (included) would give you a total of 37.5mm. Baader VIP Barlow is at 2x when distance to sensor is 64mm, so in this case magnification would be 1.57. (same result if you use ZWO ADC body instead of two spacers) If you use only one 15mm spacer it would be 1.35x. There are also 7.5mm spacers if you want to nail it. It is a very well made barlow and incredibly useful. It is not cheap, though (almost 190USD). For 300 USD you can get ASI678, I bought it for C8 because it needs no barlow at 2 micron.

IMHO for C8 ADC should definitely be considered. 100mm refractor there is not enough dispersion to correct it precisely via FC.


Edited by BGazing, 22 September 2022 - 11:12 AM.

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#3 iwols

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Posted 22 September 2022 - 11:22 AM

thanks

 

Yes ,you need 5x pixel size, so 1.45 or thereabout. 7x in great seeing...

You can try custom Siebert barlow.

I got myself a Baader VIP barlow (for solar and planetary on small refractor), it is modular and you can adjust the spacing and magnification as you wish.

Asi 462 has 12.5 mm depth to sensor, 5mm will go to the 1.25mm nose, so 7.5mm. Screwing VIP Barlow nose and two 15mm spacers (included) would give you a total of 37.5mm. Baader VIP Barlow is at 2x when distance to sensor is 64mm, so in this case magnification would be 1.57. (same result if you use ZWO ADC body instead of two spacers) If you use only one 15mm spacer it would be 1.35x. There are also 7.5mm spacers if you want to nail it. It is a very well made barlow and incredibly useful. It is not cheap, though (almost 190USD). For 300 USD you can get ASI678, I bought it for C8 because it needs no barlow at 2 micron.

IMHO for C8 ADC should definitely be considered. 100mm refractor there is not enough dispersion to correct it precisely via FC.

thanks im using an adc at the minute here is my setup

planet.jpg



#4 iwols

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Posted 22 September 2022 - 11:35 AM

so coud i just swap the barlow then? and leave the adc where it is thanks



#5 SkyHunter1

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Posted 22 September 2022 - 11:36 AM

Yes ,you need 5x pixel size, so 1.45 or thereabout. 7x in great seeing...

You can try custom Siebert barlow.

I got myself a Baader VIP barlow (for solar and planetary on small refractor), it is modular and you can adjust the spacing and magnification as you wish.

Asi 462 has 12.5 mm depth to sensor, 5mm will go to the 1.25mm nose, so 7.5mm. Screwing VIP Barlow nose and two 15mm spacers (included) would give you a total of 37.5mm. Baader VIP Barlow is at 2x when distance to sensor is 64mm, so in this case magnification would be 1.57. (same result if you use ZWO ADC body instead of two spacers) If you use only one 15mm spacer it would be 1.35x. There are also 7.5mm spacers if you want to nail it. It is a very well made barlow and incredibly useful. It is not cheap, though (almost 190USD). For 300 USD you can get ASI678, I bought it for C8 because it needs no barlow at 2 micron.

IMHO for C8 ADC should definitely be considered. 100mm refractor there is not enough dispersion to correct it precisely via FC.

+ 1 on the Siebert Barlow. I used a Siebert 1.5x on the mars shot below. Hoping to use it soon on Saturn and Jupiter. Go to the Siebert Site and give him a call. Harry is very helpful and can suggest what's best for you. 

 

MarsThe Final Cut redder

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#6 iwols

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Posted 22 September 2022 - 11:52 AM

thanks im in the uk unfortunately



#7 BGazing

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Posted 22 September 2022 - 01:39 PM

so coud i just swap the barlow then? and leave the adc where it is thanks

ADC is 29mm optical length, I have the same and did the same calculations. I see that you can mount it directly to camera, I needed male to male T2.

With 29mm optical length and 'pure' 7.5mm of additional sensor distance when you mount ADC, you will be at 36.5mm, so right about perfect magnification. Barlow element of the VIP just screws into the bottom of the ADC instead of its 1.25x nose.

 

https://www.firstlig...-125-and-2.html

 

Here is instruction on using it and modifying its magnification factor

https://www.baader-p..._vip_barlow.pdf


Edited by BGazing, 22 September 2022 - 01:42 PM.

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#8 iwols

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Posted 22 September 2022 - 02:15 PM

so its adc - barlow-camera?



#9 iwols

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Posted 22 September 2022 - 02:21 PM

so its adc - barlow-camera?

do you have an image of your setup please


Edited by iwols, 22 September 2022 - 02:21 PM.


#10 BGazing

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Posted 22 September 2022 - 02:31 PM

so its adc - barlow-camera?

It is barlow, adc, camera...always barlow before the adc, although native f/10 is probably enough for ADC to work with.

It is simply your setup that you have above, except that instead of powermate you screw in the bottom part of the barlow. It has a form factor of ADC nosepiece, except that it houses a barlow element.

If you really want, I can take photos of how it is assembled...


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#11 iwols

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Posted 22 September 2022 - 03:11 PM

yes please that would be great



#12 BGazing

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Posted 22 September 2022 - 03:59 PM

Here it is, nosepiece with the barlow element, body of the camera, t2 male to male ring to attach ADC body to the camera and camera body. Next pic assembled, cat is optional.

Attached Thumbnails

  • photo_2022-09-22_22-48-34.jpg
  • photo_2022-09-22_22-48-51.jpg

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#13 dcaponeii

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Posted 22 September 2022 - 04:27 PM

The only difference in my case is the I have camera rotator between my ADC and the camera so that as I rotate the ADC to horizontal I can keep the camera aligned with RA/DEC
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#14 iwols

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Posted 22 September 2022 - 06:18 PM

Here it is, nosepiece with the barlow element, body of the camera, t2 male to male ring to attach ADC body to the camera and camera body. Next pic assembled, cat is optional.

thank you very much,do you have  a  close up for the barlow as it isnt  what i thought it would look like(is it this one)

 

https://www.rotherva...arlow-lens.html

 

,didnt know it fitted into a nose piece,and do you have any sample images with this setup please and what scope are you using it with, once again thanks


Edited by iwols, 22 September 2022 - 06:27 PM.


#15 BGazing

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Posted 23 September 2022 - 03:30 AM

thank you very much,do you have  a  close up for the barlow as it isnt  what i thought it would look like(is it this one)

 

https://www.rotherva...arlow-lens.html

 

,didnt know it fitted into a nose piece,and do you have any sample images with this setup please and what scope are you using it with, once again thanks

It is the same barlow like in the picture, but the parts disassemble and reassemble as you wish in order to achieve the desired distance from sensor. Distance of the barlow from sensor dictates barlow magnification, the whole setup is incredibly flexible. In post no 7 here I have provided a link to Baader instructions on spacing and calculating magnification.

I used this so far only with my 100mm refractor, my C8 is in our cottage and I for it my 678 will be used without barlow as it is 2 micron and C8 is f/10. My refractor is f/7.4 and I use just the barlow nose and small spacing to get to f/10 because my camera works best at f/10.

The photo I made with this small setup can be seen here, but again, it is always about the seeing, you just set up conditions so that you can use that seeing. Here's one of my first tries. Last page, same thread you can see that when seeing and transparency are bad no camera and barlow can push it very far.

If you want to use your current camera with your C8, VIP barlow is my recommendation because it is incredibly flexible. If you do not want to faff with a barlow, you can get ASI678.


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#16 iwols

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Posted 23 September 2022 - 04:54 AM

It is the same barlow like in the picture, but the parts disassemble and reassemble as you wish in order to achieve the desired distance from sensor. Distance of the barlow from sensor dictates barlow magnification, the whole setup is incredibly flexible. In post no 7 here I have provided a link to Baader instructions on spacing and calculating magnification.

I used this so far only with my 100mm refractor, my C8 is in our cottage and I for it my 678 will be used without barlow as it is 2 micron and C8 is f/10. My refractor is f/7.4 and I use just the barlow nose and small spacing to get to f/10 because my camera works best at f/10.

The photo I made with this small setup can be seen here, but again, it is always about the seeing, you just set up conditions so that you can use that seeing. Here's one of my first tries. Last page, same thread you can see that when seeing and transparency are bad no camera and barlow can push it very far.

If you want to use your current camera with your C8, VIP barlow is my recommendation because it is incredibly flexible. If you do not want to faff with a barlow, you can get ASI678.

thanks again appreciated,so to sum it all up what do you think you have gained with your C8 using 462 v 462 with barlow v asi 678 please ,thanks



#17 BGazing

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Posted 23 September 2022 - 08:15 AM

thanks again appreciated,so to sum it all up what do you think you have gained with your C8 using 462 v 462 with barlow v asi 678 please ,thanks

I only recently started imaging, but as other has explained to me and the FAQ on planetary imaging in this subforum would suggest, you should image at focal ratio of approx 5x size of camera pixel. You can go a little more or little less, but given that imaging makes sense only in relatively good seeing, 5x is the ballpark.

ASI 462 has pixel size of 2.9, so you need to be at f/14.5 when imaging, otherwise you are undersampling, i.e. not using the full potential of your telescope. Photons are fighting for pixels, instead of being spread around nicely. That is why you need 1.4x-1.5x barlow factor. 

ASI 678 has 2 micron pixel so it works in C8 as critical sampling to full potential without any barlows. 

All this and more can be found here https://www.cloudyni...ated-july-2022/


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#18 AstroBert

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Posted Yesterday, 10:46 PM

Hi, likely others have shown comparable methods, but just in case the attached file describes a trick I used to convert at no cost a Celestron 2X Barlow into something approaching 1.5X, for use with a ZWO camera. Initial trials gave images with no apparent degradation due to this modest departure from what was probably an optimized design for the original 2X function.

Attached File  Barlow 100322 AstroBertc.pdf   474.5KB   12 downloads 


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