TPO Ultrawide 180 f/4.5 Astrophotography Lens and Guide Scope (NEW 4/15/21)

 

TPO Ultrawide 180 f/4.5 Astrophotography Lens and Guide Scope

Peter Detterline

 

Dave asked me to test out a new telescope system for wide field astrophotography applications.  The TPO Ultrawide 180 f/4.5 Astrophotography lens and guide scope available from ,https://optcorp.com/products/tpo-ultra-wide-180-astrophotography-lenshas been getting a lot of rave reviews. I’m going to talk about the setup using an EAF focuser and use with both DSLR and ZWO cameras .  

Included Items:                                                                 

TPO UltraWide 180 Astrophotography Lens

Three-Element Reducer with Reducer Extension Tube

Extension Tube 1

Extension Tube 2

1.25" Adapter

Tube Rings

Vixen/Finder Dovetail Plate

Arca-Swiss Dovetail Plate

Dovetail Stalk

Hex Key 

The focus on such a small fast system is particularly sensitive.  So taking focus issues out of the equation is a necessary and important step.  Highly recommended is an EAF focuser will allow you to use the ASIair software routine to automatically focus the telescope. Deep Sky Dad makes a kit available at https://deepskydad.com/autofocuser/askar180/eaf.  Askar is the European equivalent of the TPO, so don’t worry it will fit the lens. Follow the instructions carefully; space-wise everything is going to be a tight fit. Pay special attention to tightening the rings for maximum and minimum focus.  Watching the video is a big help in understanding how the unit works. 

The biggest issue you will face is that The EAF rings will have to be loosened and adjusted to change from the DSLR to the ZWO configurations due to changing the extenders.  This takes time and there isn’t a short cut.

Setup for DSLR

The camera used was a Canon 60Da outfitted with a clip in STC light pollution filter.  It needs to setup fairly tight to the lens system so use the shortest extender to connect it to the camera.  In this setup the guide scope was connected to the shoe on top of the camera.  This shoe mount was purchased for $40 from Idea Engineering and can be found at: https://www.ideaengineering.us/?ec_search=IDEA-VFDSLR+V4 .  The ZWO 120 mini does a wonderful job as a guide scope with this setup.

Images

As expected, the field of view is very wide with the DSLR.  The Orion Nebula and the Horsehead are both in the field as it extends about 4.5° x 8.5°.  The exposure length is 180 seconds.  The summer Milky Way would be a great target with this setup as would the Veil and North American Nebula.

Setup for ZWO

The setup for the ZWO camera also needs to include the Starizona filter slider, https://starizona.com/products/starizona-filter-slider-complete-system, so various 2” filters can be added to the system.  It is possible to screw the filter onto the end of the lens, but this is not ideal; the filter should be as close to the camera as possible.  Using filters is an essential feature for our suburban skies at home.  

The EAF position on the top doesn’t make this an ideal setup for guiding.  The solution we came up with was a side by side system with a guide scope on the opposite side along with the ASIair Pro. This allows access to both systems and makes cord management easy. 

 

Images

We start with the Heart and Soul Nebula to get an idea of the field of view which is about 3° x 5.5°.  The picture is a combination of 10 stacked images at 180- second exposures each using the L-extreme filter.

The same setup was also used with the California Nebula.  The picture is a combination of 10 stacked images at 180- second exposures each using the L-extreme filter.

The Elephant Trunk Nebula, IC 1396.  The picture is a combination of 10 stacked images at 300- second exposures each using the L-enhance filter.

The North American and Pelican nebulae taken with an L-Extreme fiter.  This is a combination of 20 stacked images at 300 seconds.

Conclusion

This is a beautiful lightweight setup for travel.  However, the EAF I feel is essential for good focus and ease of operation and that adds considerable weight and bulk.  The setup for the ZWO camera with the side by side system is not ideal for air travel; there are just too many components.  For traveling, the Canon DSLR would be more self –contained and you could get all the components easily in carry-on luggage.