Image size at focal plane of an 155f7 EDFS


marsh.family
 

Hi, hoping for some insight

I am considering a new camera/filter wheel and am wondering with the 2.7" focuser whether there would be vignetting for a full frame sensor.  Also, I'm wondering whether a 36mm filter would be wide enough to not vignette the light from the objective should I choose a full frame sensor. Or does one need the 2" filter.

Thanks,

Chris


William L
 

2.7” = 68.6mm, so vignetting won’t be a problem. The diagonal of a full frame sensor is 36mm x 24mm, or 43mm, so 36mm filters would vignette. I use 2” filters for my full frame cameras, without any problems. 


Roland Christen
 

The 2.7" focuser will not vignet. The 36mm filter will vignet quite a bit. You will need a field flattener in either case.

Roland

-----Original Message-----
From: marsh.family <marsh.family@...>
To: main@ap-ug.groups.io
Sent: Mon, Jan 10, 2022 3:32 pm
Subject: [ap-ug] Image size at focal plane of an 155f7 EDFS

Hi, hoping for some insight

I am considering a new camera/filter wheel and am wondering with the 2.7" focuser whether there would be vignetting for a full frame sensor.  Also, I'm wondering whether a 36mm filter would be wide enough to not vignette the light from the objective should I choose a full frame sensor. Or does one need the 2" filter.

Thanks,

Chris


marsh.family
 

Thanks for the advice – it’s much appreciated.

 

Regards,

 

Chris

 

From: main@ap-ug.groups.io <main@ap-ug.groups.io> On Behalf Of Roland Christen via groups.io
Sent: January 10, 2022 6:10 PM
To: main@ap-ug.groups.io
Subject: Re: [ap-ug] Image size at focal plane of an 155f7 EDFS

 

The 2.7" focuser will not vignet. The 36mm filter will vignet quite a bit. You will need a field flattener in either case.

 

Roland

 

-----Original Message-----
From: marsh.family <marsh.family@...>
To: main@ap-ug.groups.io
Sent: Mon, Jan 10, 2022 3:32 pm
Subject: [ap-ug] Image size at focal plane of an 155f7 EDFS

Hi, hoping for some insight

I am considering a new camera/filter wheel and am wondering with the 2.7" focuser whether there would be vignetting for a full frame sensor.  Also, I'm wondering whether a 36mm filter would be wide enough to not vignette the light from the objective should I choose a full frame sensor. Or does one need the 2" filter.

Thanks,

Chris


marsh.family
 

A follow-up question for those who have used a mono-camera in a light polluted urban environment.

 

To date I’ve been using a colour camera with a narrow band filter.  I’ve had moderate success and was very surprised by the ambient light suppression.  To the point where it was easy to capture images on almost any clear night.

 

Now considering a mono camera, I’m wondering if anyone can share how the LRGB filters work in such an environment.  Or does the moon and ambient light become a much bigger concern? 

 

Thanks for your thoughts,

 

Regards,

 

Chris

 

From: main@ap-ug.groups.io <main@ap-ug.groups.io> On Behalf Of Roland Christen via groups.io
Sent: January 10, 2022 6:10 PM
To: main@ap-ug.groups.io
Subject: Re: [ap-ug] Image size at focal plane of an 155f7 EDFS

 

The 2.7" focuser will not vignet. The 36mm filter will vignet quite a bit. You will need a field flattener in either case.

 

Roland

 

-----Original Message-----
From: marsh.family <marsh.family@...>
To: main@ap-ug.groups.io
Sent: Mon, Jan 10, 2022 3:32 pm
Subject: [ap-ug] Image size at focal plane of an 155f7 EDFS

Hi, hoping for some insight

I am considering a new camera/filter wheel and am wondering with the 2.7" focuser whether there would be vignetting for a full frame sensor.  Also, I'm wondering whether a 36mm filter would be wide enough to not vignette the light from the objective should I choose a full frame sensor. Or does one need the 2" filter.

Thanks,

Chris