Skymax 127 low power for goto

[OK Apricot]

It seems each time I use the AZ GTi I get slightly better results, the latest time with a few targets being placed in the FOV with the standard 25mm. I was thinking that using a lower power EP, around 40mm, I'd be getting better results - an object in the fov every time. From there I can then fine tune and track my object. What budget EPs can people recommend? For the price I was considering the astro essentials 40mm. Key factors are low magnification and wide true fov. Would also need to be 1.25". 

Edited March 3, 2022 by OK Apricot
Details

[Cosmic Geoff]

You should not need a 40mm eyepiece for that purpose.  With the Nexstars (including the Celestron equivalent of your scope) I have found that the Goto alignment if properly done will place objects within the field of a 25mm eyepiece.  If you are not getting that degree of accuracy with your Az GTi, some attention to the mount or alignment procedure may be required.

BTW you might as well have a 32mm 1.25" Plossl, as the actual FOV will be the same as with a 40mm 1.25" Plossl.

[Nik271]

I have a 40mm plossl but instead I tend to use the 32mm because the true  field of views are almost identical, just over 1 degree. If you have light polluted skies then you don't want very low magnification because the sky background becomes too bright.

[bosun21]

When I first got my 127 Go to I used a Celestron Omni 32mm for finding my targets. However if you do a few things during the alignment procedure it increases the accuracy of the Go to substantially. 1/ Ensure that your tripod is accurately leveled. 2/ On the first star alignment try and ensure that the last two movements are with the up/right keys. 3/ When selecting your second star choose one to the right and higher than the first and ONLY use the up/right keys again to centre the star.( if you overshoot slightly, allow the earth rotation to bring it back) 4/  If possible use an eyepiece with an illuminated reticle to centre the alignment stars, 

By doing these steps I can use a 25 or 15mm eyepiece and my targets will be in my FOV

[ScouseSpaceCadet]

As described above, a 32mm plossl is likely the best budget candidate. I've owned the Astro Essentials version and it was good for the price.

[Stu]

Agreed, in terms of field of view the 32mm makes most sense as it will be virtually the same as the 40mm because it is limited by the field stop of the 1.25” barrel.

The only reason to go for a 40mm is that it will offer a slightly large exit pupil which can help with filtered views through a UHC or OIII filter.

[OK Apricot]

Thanks guys. I'll look into the 32mm. 

I'm still learning this mount and want to persevere with it before just sending it back, you know, in case it's me doing something not quite right. I do take my time with levelling and alignment as mentioned and recently have had some objects in the FOV, and I'd hope the wider field of a lower power EP would turn that some into most. That'll do for me for the time being. 

[Richard_B]

2 hours ago, OK Apricot said:

Thanks guys. I'll look into the 32mm. 

I'm still learning this mount and want to persevere with it before just sending it back, you know, in case it's me doing something not quite right. I do take my time with levelling and alignment as mentioned and recently have had some objects in the FOV, and I'd hope the wider field of a lower power EP would turn that some into most. That'll do for me for the time being. 

 

14 hours ago, bosun21 said:

When I first got my 127 Go to I used a Celestron Omni 32mm for finding my targets. However if you do a few things during the alignment procedure it increases the accuracy of the Go to substantially. 1/ Ensure that your tripod is accurately leveled. 2/ On the first star alignment try and ensure that the last two movements are with the up/right keys. 3/ When selecting your second star choose one to the right and higher than the first and ONLY use the up/right keys again to centre the star.( if you overshoot slightly, allow the earth rotation to bring it back) 4/  If possible use an eyepiece with an illuminated reticle to centre the alignment stars, 

By doing these steps I can use a 25 or 15mm eyepiece and my targets will be in my FOV

Thanks for this tip - I'll have a go as I am having difficulty with this mount

[Richard_B]

2 hours ago, OK Apricot said:

Thanks guys. I'll look into the 32mm. 

I'm still learning this mount and want to persevere with it before just sending it back, you know, in case it's me doing something not quite right. I do take my time with levelling and alignment as mentioned and recently have had some objects in the FOV, and I'd hope the wider field of a lower power EP would turn that some into most. That'll do for me for the time being. 

I use a BST Starguider 25mm as my widest lens - this is with a ST102 though which gives me the equivalent of a x20 magnification

[OK Apricot]

25mm on my Mak is 3x that! Hence the tight alignment tolerances - things aren't quite perfect at the moment but very close, and a 32-40mm would give that slightly wider field so that the object I'm looking for is in the fov. 

[Louis D]

Could you mount an 8x50 RACI finder scope on your OTA?  That might help you see the object in a wider field after goto and make centering easier.

[OK Apricot]

I could, but it's more faffing about than I'd like at my newbie stage. I also think it would struggle to show on the dimmer DSOs anyway. 

Just reading FLOs page and it says the 40mm might be better for afocal photography - that's a bit more interesting 🤔 I do like to snap a picture here or there with my phone after all. 

[Louis D]

1 hour ago, OK Apricot said:

I could, but it's more faffing about than I'd like at my newbie stage. I also think it would struggle to show on the dimmer DSOs anyway. 

Just reading FLOs page and it says the 40mm might be better for afocal photography - that's a bit more interesting 🤔 I do like to snap a picture here or there with my phone after all. 

Using a smartphone camera, the 40mm would yield a circular image with most wide angle cameras.  You'd have to use a telephoto camera to fill the frame.  A 32mm Plossl would work just as well and yield both more image scale and a larger image circle.

My favorite for afocal photography is a 22mm 70 degree AT AF70 which is the same as the Omegon Redline SW.  However, it is 2" only.  The long eye relief, wide field of view, and good image scale really come together in it.

[Adam J]

On 03/03/2022 at 20:46, OK Apricot said:

It seems each time I use the AZ GTi I get slightly better results, the latest time with a few targets being placed in the FOV with the standard 25mm. I was thinking that using a lower power EP, around 40mm, I'd be getting better results - an object in the fov every time. From there I can then fine tune and track my object. What budget EPs can people recommend? For the price I was considering the astro essentials 40mm. Key factors are low magnification and wide true fov. Would also need to be 1.25". 

You may be better off with the 32 as the 40 has lower apparent FOV. 

[OK Apricot]

Thanks everyone for the advice 👍