With a 1 m dish, observing astronomical masers is challenging but not impossible if you use a low-noise receiver and target the strongest sources.
The most practical maser lines are:
Maser Type Frequency Suitability for 1 m Dish
Water (H2O) maser 22.235 GHz Possible on the very strongest sources with excellent equipment
Hydroxyl (OH) maser 1612, 1665, 1667, 1720 MHz Most realistic target for a small dish
Methanol maser 6.668 GHz Possible only for the brightest sources and low-noise systems
Strong maser sources that amateur-sized systems have detected include:
W49N (strong water maser)
Orion KL (water and OH masers)
W3(OH) (OH and methanol masers)
Cepheus A (water masers)
For a 1 m dish specifically:
1. OH masers around 1.6 GHz are the easiest because:
The dish beam is wide.
Receivers are relatively simple.
System temperatures can be kept low.
2. Methanol masers at 6.7 GHz are possible if:
Your dish surface accuracy is good.
You use a low-noise LNA (<1 dB NF).
You integrate for long periods.
3. Water masers at 22 GHz are the most difficult because:
Atmospheric absorption is significant.
Dish pointing must be accurate.
Surface accuracy becomes important.
A rough estimate for a 1 m dish at 1.6 GHz gives about 12 dBi gain, which is generally insufficient for routine maser work unless the source is exceptionally strong and long integrations are used. Many amateur maser observers use dishes of 2–5 m diameter for reliable detections.
Since you already work in radio astronomy and have experience with the hydrogen line, the most achievable maser project with a 1 m dish would be an OH maser receiver near 1665/1667 MHz. The receiver technology is very similar to what is used for 1420 MHz observations, making it a natural next step.