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Orion Optics GX250 F/4.8 Newtonian



Introduction

I've been a "serious" amateur astronomer for 15 years and a member of the Norwich Astronomical Society (NAS) for most of that time. Finally I thought it was high time I bought myself a telescope.

Being primarily a "faint fuzzy" observer I decided that a fast newtonian was the best way to go. With £1000 to spend I finally chose the Orion Optics GX250 F4.8. Unfortunately I couldn't afford the GPDX mount so I just bought the OTA and went for a Helios EQ4 mount instead.

Delivery

I ordered the OTA and mount through a local camera/telescope dealer in Ipswich. This meant that I didn't have to pay carriage and that they would deal with the suppliers for me. They were very helpful. Orion Optics gave me delivery dates which were repeatedly missed. I finally received the OTA after nearly eight weeks. Not too good when you consider Orion Optics quoted a delivery within seven days!

First Impressions

I bought my the GX250 (OTA only) about eight weeks ago and I am pleased I did. The optics are clean and bright, the tube and fittings seem well made. For £440 I consider it very good value for money. The Orion Optics dovetail plate fit the EQ4 with no problems, but I found that the counterweights supplied with the EQ4 were not enough to balance the GX250.

First Light

The first clear night after taking delivery, happened to be club night at the NAS. Once set up, I turned the telescope to Jupiter. Urgh! The planet was visible but badly distorted. With horrid thoughts spinning through my head I carried the telescope back indoors.

The collimation was way off. After 15 minutes we had it pretty well collimated and out we went again. This time the image was very nice. The images either side of focus weren't perfect but when focused it was more than useable.

Build quality

After usiug the GX250 for a few more nights, I noticed that the collimation kept being disturbed. The collimation screws are actually wing nuts through the cell of the 'scope. This leaves them VERY easy to knock and thus very easy to ruin your collimation as well as meaning you cannot stand the telescope upright. I have since replaced the wing nuts with nylon locking nuts and put three rubber feet on the bottom of the cell to protect them further.

The tube is well made rolled steel with a cast metal ring at the top and a cast metal mirror cell. I paid extra for the 8x50 right angle finder. The NAS also bought one about the same time. Their's was unable to focus and the objective cell was badly scratched. Mine is better, but the eyepeice is pretty poor giving very blurred images anywhere but near the centre of the view. While collimating the telescope I noticed that the flat is well centred but is not correctly positioned below the focuser which in turn is not square to the tube.

Optical Performance

After spening more time collimating it properly, the optical performance is now to the high standard I expected from an Orion Optics instrument. Over the last few weeks I have had the chance to compare my GX250 with several other 'scopes, from an ETX to a Takahashi, and I think I have the best value for money out of the lot! The image quality is easily equal to a 10in Meade LX200, and currently beats the NAS's 10in Newtonian which has a Horace Dall 1/20 wave mirror!

Summary

Great optics, but you'll probably have to wait for them and be prepared to fiddle with it to bring the rest of the 'scope up to the standard of the optics.



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